document_title: Vegas Golden Knights

question_text: when did the vegas golden knights become a team

text: Vegas Golden Knights

text: History[edit]

text: Background and establishment[edit]

text: The NHL has had a presence in Las Vegas since 1991, when an outdoor game was held in Las Vegas, with the Los Angeles Kings facing the New York Rangers outside Caesars Palace in a preseason exhibition game. The city has since hosted the Frozen Fury, a pre-season competition between the Los Angeles Kings and the Colorado Avalanche, and the NHL Awards ceremonies have been held in Las Vegas since 2009.[6] In 2009, the media speculated about a plan involving Hollywood producer Jerry Bruckheimer to move the Phoenix Coyotes to Nevada.[7]

text: Rumors of a Las Vegas expansion team surfaced again in August 2014, pointing to a new indoor arena on the Strip (built as a joint venture between Anschutz Entertainment Group, owners of the Los Angeles Kings, and MGM Resorts International) as the potential home arena, although these rumors were denied by the league.[8][9][10] In November 2014, an unconfirmed report stated that the league had selected billionaire businessman Bill Foley and the Maloof family (former owners of the National Basketball Association's Sacramento Kings, and founders of the Palms Casino Resort) to lead the ownership group for a Las Vegas expansion team.[11][12] In December 2014, the NHL's board of governors decided to allow Foley to hold a season ticket drive to gauge interest in a Las Vegas team, though league commissioner Gary Bettman also warned the media to "[not] make more out of this than it is".[13][14] The season ticket drive began in February 2015, with interested parties placing ten percent deposits for the 2016–17 season.[15] The drive drew 5,000 deposits in its first day and a half, and reached its goal of 10,000 deposits by April 2015.[15][16]

text: In June 2015, the league officially opened the window for prospective owners to bid on expansion teams. By this point, Foley had secured more than 13,200 season-ticket deposits. Two expansion applications were submitted: Foley's application for a Las Vegas team, and a bid from Quebecor to revive the Quebec Nordiques at a new arena in Quebec City. Both Las Vegas and Quebec were invited to move into Phase II of the league expansion bid in August 2015,[17] and subsequently advanced to Phase III.

text: At the league owners' meeting on June 22, 2016, in Las Vegas, the Las Vegas expansion bid was approved by a unanimous vote, with play to begin in the 2017–18 NHL season.[18] The team became the first major professional sports franchise to be based in Las Vegas, and the first NHL expansion team since 2000.[19] Foley committed to pay the league's $500 million expansion fee[20] and began the process of hiring the team's principal staff and determining its official identity. Foley announced that former Washington Capitals general manager George McPhee would be the franchise's first general manager.[21] On November 22, 2016, the name was revealed as the Vegas Golden Knights.

text: Start of operations: 2017–present[edit]

text: On March 1, 2017 (coinciding with the league's trade deadline), the team completed its expansion fee payments and filings, making it eligible to formally begin operations such as free agent acquisition, and participation in league meetings.[22] Five days later, the Golden Knights made its first personnel move by signing Reid Duke to a three-year entry-level contract.[23][24]

text: The team announced inaugural head coach Gerard Gallant on April 13, 2017.[25] Over the next two months, the Golden Knights developed their farm system, announcing affiliations with the Chicago Wolves of the American Hockey League and the Quad City Mallards of the ECHL.[26][27]

text: The team participated in the 2017 NHL Expansion Draft on June 21, 2017, selecting an available player from all 30 teams in the NHL. The draft picks were announced at T-Mobile Arena during the NHL Awards ceremony. Some notable selections included goalie Marc-Andre Fleury from the Pittsburgh Penguins and winger James Neal from the Nashville Predators. At the 2017 NHL Entry Draft, Cody Glass was the first player selected by the Golden Knights. The Golden Knights played their first game on October 6 against the Dallas Stars with Neal scoring the franchise's first two goals en route to their first victory.[28]

text: The team's inaugural home game was played on October 10, 2017, hosting the Arizona Coyotes as the second game of a home-and-home series. In the aftermath of the October 1 mass shooting, the pre-game ceremonies honored the victims of the attack, and the team issued an appeal for donations to its charitable arm.[29] With their 5–2 win, the Golden Knights increased their unbeaten streak to start the season to 3–0, an NHL record for an expansion team.[30][31][32] The Golden Knights are the first team in NHL history to have started their inaugural season winning eight of their first nine games. During their tenth game, goaltender Oscar Dansk was injured becoming third Golden Knights' goaltender to be injured during the season after losing starters Fleury and the recently acquired Malcolm Subban, forcing the team to start a fourth goaltender in 11 games with Maxime Lagace.[33] Fifteen games into the season, Vadim Shipachyov became the first player to retire from the NHL as a Golden Knight when he decided to return to the Kontinental Hockey League. In December, the Golden Knights set another NHL expansion team record of six straight wins, a record they had previously missed when they lost their tenth game of the season, and established a new NHL record with eight straight wins.[34][35][36] On February 1, 2018, the Golden Knights set the expansion team record for wins in a debut season with 34 wins after only 50 games,[37] and then on February 21, 2018, set a record for most points by an expansion team in the inaugural season with 84.[38]

text: Team information[edit]

text: Team name[edit]

text: The team's name includes "Knights" as a homage to the Black Knights of the United States Military Academy, Foley's alma mater, and because knights were, according to Foley, "the epitome of the warrior class".[39][40] Foley had hoped to name his team the Black Knights, but dropped that plan after encountering resistance from federal officials. Foley was unable call the team the "Vegas Knights" due to the London Knights owning the "Knights" name in Canada.[40][41][42]

text: "Golden" was included in the name because gold is, as Foley stated, the "No. 1 precious metal", and because Nevada is the largest gold-producing state in the country.[40][43]

text: "Las" was omitted from the team's name because, according to Foley, residents tend to refer to the city simply as "Vegas", and because a four-word name would have been too long.[43]

text: The United States Army initially expressed concern after the Golden Knights' name was announced, because their parachute team uses the same nickname.[41] The Army later disputed the trademark and colors of the team during its first season, to which the team responded: "We are not aware of a single complaint from anyone attending our games that they were expecting to see the parachute team and not a professional hockey game."[44] An objection was also raised by the College of Saint Rose because its sports teams use the same name; the Vegas team's initial trademark application was denied as a result, but was later approved on appeal.[45] The team did clear the name with Clarkson University, which also uses the name Golden Knights.[46]

text: Logos and colors[edit]

text: The team's primary logo is a barbute helmet, superimposed on a black and gold seal, with a V-shaped opening.[39][43]

text: The secondary logo is two crossing swords behind a red star, designed to resemble a star found on the landmark Welcome to Fabulous Las Vegas sign.[43]

text: The team's primary color is steel gray, which is said to represent "strength and durability".[43][1] The other team colors are gold, red (found in the Las Vegas skyline and at Red Rock Canyon), and black (for "power and intensity").[1]

text: Mascot[edit]

text: The Golden Knights' mascot is a Gila monster named Chance. He was unveiled at the team's second home game on October 13, 2017.[47][48] The team opted against using a knight for a mascot because it found that knight mascots used by other teams were not very child-friendly.[49]

text: Players and personnel[edit]

text: Current roster[edit]

text:
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talk
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text: Updated February 27, 2018.[50][51]

text:
#
Nat
Player
Pos
S/G
Age
Acquired
Birthplace

7001410000000000000♠41
France !
Bellemare, Pierre-EdouardPierre-Edouard Bellemare
6.0 !LW
L
32
2017
Le Blanc-Mesnil, France

7001400000000000000♠40
United States !
Carpenter, RyanRyan Carpenter
4.3 !C/RW
R
27
2017
Oviedo, Florida

7001280000000000000♠28
Canada !
Carrier, WilliamWilliam Carrier
6.0 !LW
L
23
2017
LaSalle, Quebec

7001210000000000000♠21
Canada !
Eakin, CodyCody Eakin
4.0 !C
L
26
2017
Winnipeg, Manitoba

7000500000000000000♠5
Canada !
Engelland, DerykDeryk Engelland (A)
2.0 !D
R
35
2017
Edmonton, Alberta

7001290000000000000♠29
Canada !
Fleury, Marc-AndreMarc-Andre Fleury
1.0 !G
L
33
2017
Sorel-Tracy, Quebec

7001560000000000000♠56
Finland !
Haula, ErikErik Haula
6.0 !LW
L
26
2017
Pori, Finland

7001770000000000000♠77
Canada !
Hunt, BradBrad Hunt
2.0 !D
L
29
2017
Maple Ridge, British Columbia

7001380000000000000♠38
Czech Republic !
Hyka, TomasTomas Hyka
7.0 !RW
L
24
2017
Mladá Boleslav, Czech Republic

7001710000000000000♠71
Sweden !
Karlsson, WilliamWilliam Karlsson
4.0 !C
L
24
2017
Märsta, Sweden

7001330000000000000♠33
Canada !
Lagace, MaximeMaxime Lagace
1.0 !G
L
25
2017
Longueuil, Quebec

7001240000000000000♠24
Sweden !
Lindberg, OscarOscar Lindberg
4.0 !C
L
26
2017
Skellefteå, Sweden

7001810000000000000♠81
Canada !
Marchessault, JonathanJonathan Marchessault
4.0 !C
R
27
2017
Cap-Rouge, Quebec

7000300000000000000♠3
Canada !
McNabb, BraydenBrayden McNabb
2.0 !D
L
27
2017
Davidson, Saskatchewan

7001150000000000000♠15
USA !
Merrill, JonJon Merrill
2.0 !D
L
26
2017
Oklahoma City, Oklahoma

7000600000000000000♠6
Canada !
Miller, ColinColin Miller
2.0 !D
R
25
2017
Sault Ste. Marie, Ontario

7001180000000000000♠18
Canada !
Neal, JamesJames Neal (A)
7.0 !RW
L
30
2017
Whitby, Ontario

7001920000000000000♠92
Czech Republic !
Nosek, TomasTomas Nosek
4.0 !C
L
25
2017
Pardubice, Czechoslovakia

7001570000000000000♠57
Canada !
Perron, DavidDavid Perron (A)
6.0 !LW
R
29
2017
Sherbrooke, Quebec

7001750000000000000♠75
Canada !
Reaves, RyanRyan Reaves
7.0 !RW
R
31
2018
Winnipeg, Manitoba

7001470000000000000♠47
Switzerland !
Sbisa, LucaLuca Sbisa (A)
2.0 !D
L
28
2017
Ozieri, Italy

7001880000000000000♠88
United States !
Schmidt, NateNate Schmidt
2.0 !D
L
26
2017
St. Cloud, Minnesota

7001190000000000000♠19
Canada !
Smith, ReillyReilly Smith (A)
7.0 !RW
L
26
2017
Etobicoke, Ontario

7000400000000000000♠4
Canada !
Stoner, ClaytonClayton Stoner
2.0 !D
L
33
2017
Port McNeill, British Columbia

7001300000000000000♠30
Canada !
Subban, MalcolmMalcolm Subban
1.0 !G
L
24
2017
Toronto, Ontario

7001900000000000000♠90
Slovakia !
Tatar, TomasTomas Tatar
6.0 !LW
L
27
2018
Ilava, Czechoslovakia

7001270000000000000♠27
Canada !
Theodore, SheaShea Theodore
2.0 !D
L
22
2017
Langley, British Columbia

7001890000000000000♠89
United States !
Tuch, AlexAlex Tuch
7.0 !RW
R
21
2017
Syracuse, New York

text: Retired numbers[edit]

text: Though Vegas has not itself retired any numbers, the team is not able to issue the jersey number #99 to any of its players as that number was retired league-wide in honor of Wayne Gretzky at the 2000 NHL All-Star Game.[52]

text: Head coaches[edit]

text: Gerard Gallant (2017–present)

text: General managers[edit]

text: George McPhee (2016[53]–present)

text: Media[edit]

text: AT&T SportsNet Rocky Mountain (formerly Root Sports) is the regional television rightsholder for all Golden Knights games not broadcast nationally by NBCSN or NBC. The team's designated market includes Nevada, Idaho, Montana, Utah, Wyoming, and parts of Arizona and California.[54][55][56] Golden Knights games on AT&T SportsNet are called by former Boston Bruins radio announcer Dave Goucher on play-by-play, and Shane Hnidy, who previously worked color for the Winnipeg Jets on TSN.[57]

text: The team has a three-year radio deal with Lotus Broadcasting.[58] Lotus airs the team's games on its Fox Sports Radio affiliate, KRLV 1340/98.9.[58] KRLV fronts a network of nine stations across Nevada, California, Arizona, and Utah.[59]

text: One game a week is also aired on the company's ESPN Deportes Radio affiliate, KENO 1460, making the team one of only three in the NHL to offer Spanish-language broadcasts.[60]


document_title: Bicameralism

question_text: number of states having bicameral legislature in india

root

text: Bicameralism

text: History of bicameral legislatures[edit]

text: The ideas that formed the basis of bicameralism trace back to theories developed in ancient Sumer, ancient India, later ancient Greece, and Rome. However, recognizable bicameral institutions first arose in Medieval Europe, associated with separate representation of different estates of the realm. For example, one house represented the aristocracy, and the other the commoners, as in the Kingdom of England.[2] Others, such as France under the Ancien Régime had a tricameral legislature known as the Estates General, which consisted of separate chambers for the clergymen, the nobility and the commoners.[3]

tag: p

text: The Founding Fathers of the United States also favoured a bicameral legislature. The idea was to have the Senate be wealthier and wiser. Benjamin Rush saw this though, and noted that, "this type of dominion is almost always connected with opulence." The Senate was created to be a stabilising force, elected not by mass electors, but selected by the State legislators. Senators would be more knowledgeable and more deliberate—a sort of republican nobility—and a counter to what Madison saw as the "fickleness and passion" that could absorb the House.[2]

text: He noted further that, "The use of the Senate is to consist in its proceeding with more coolness, with more system and with more wisdom, than the popular branch." Madison's argument led the Framers to grant the Senate prerogatives in foreign policy, an area where steadiness, discretion, and caution were deemed especially important".[2] State legislators chose the Senate, and senators had to possess significant property to be deemed worthy and sensible enough for the position. In 1913, the 17th Amendment passed, which mandated choosing Senators by popular vote rather than State legislatures.[2]

text: As part of the Great Compromise, they invented a new rationale for bicameralism in which the Senate had states represented equally, and the House had them represented by population.

text: The British Parliament is often referred to as the Mother of Parliaments (in fact a misquotation of John Bright, who remarked in 1865 that "England is the Mother of Parliaments") because the British Parliament has been the model for most other parliamentary systems, and its Acts have created many other parliaments.[4] Many nations with parliaments have to some degree emulated the British "three-tier" model. Most countries in Europe and the Commonwealth have similarly organised parliaments with a largely ceremonial head of state who formally opens and closes parliament, a large elected lower house and a smaller, upper house.[5][6]

text: Rationale for bicameralism and criticism[edit]

text: A formidable sinister interest may always obtain the complete command of a dominant assembly by some chance and for a moment, and it is therefore of great use to have a second chamber of an opposite sort, differently composed, in which that interest in all likelihood will not rule.

text: There have been a number of rationales put forward in favour of bicameralism, federal states have often adopted it, and the solution remains popular when regional differences or sensitivities require more explicit representation, with the second chamber representing the constituent states. Nevertheless, the older justification for second chambers—providing opportunities for second thoughts about legislation—has survived.[citation needed]

text: Growing awareness of the complexity of the notion of representation and the multifunctional nature of modern legislatures may be affording incipient new rationales for second chambers, though these do generally remain contested institutions in ways that first chambers are not. An example of political controversy regarding a second chamber has been the debate over the powers of the Canadian Senate or the election of the Senate of France.[7]

text: The relationship between the two chambers varies; in some cases, they have equal power, while in others, one chamber is clearly superior in its powers. The first tends to be the case in federal systems and those with presidential governments. The latter tends to be the case in unitary states with parliamentary systems.

text: There are two streams of thought: Critics believe bicameralism makes meaningful political reforms more difficult to achieve and increases the risk of gridlock—particularly in cases where both chambers have similar powers—while proponents argue the merits of the "checks and balances" provided by the bicameral model, which they believe help prevent the passage into law of ill-considered legislation.

text: Types[edit]

text: Federal[edit]

text: Some countries, such as Argentina, Australia, Austria, Belgium, Bosnia and Herzegovina, Brazil, Canada, Germany, India, Malaysia, Mexico, Pakistan, Russia, Switzerland, Nigeria, and the United States, link their bicameral systems to their federal political structure.

text: In the United States, Australia, and Mexico, for example, each state is given the same number of seats in one of the houses of the legislature, despite the total population of each state — it is designed to ensure that smaller states are not overshadowed by larger states, which may have more representation in the other house of the legislature.

text: Canada[edit]

text: In Canada, the country as a whole is divided into a number of Senate Divisions, each with a different number of Senators, based on a number of factors. These Divisions are Quebec, Ontario, Western Provinces, and the Maritimes, each with 24 Senators, Yukon, Northwest Territories, Nunavut, each with 1 Senator, and Newfoundland and Labrador has 6 Senators, making for a total of 105 Senators.

text: Senators in Canada are not elected by the people but are appointed by the Governor General on the advice of the Prime Minister. The Senate does not originate most legislation (although a small fraction of government bills are introduced in the Senate and Senators may introduce private members' bills in the same way as MPs) but acts as a chamber of revision almost always passing legislation approved by the House of Commons, made up of Members of Parliament (MPs) who are elected. The Senate must pass legislation before it becomes law and can therefore act as a wise facilitator or engage in filibuster. The Senate does not have to endure the accountability and scrutiny of parliamentary elections. Therefore, the bicameral structure of Canadian parliament is more de jure than de facto.[citation needed]

text: Australia[edit]

text: The bicameral Parliament of Australia consists of two Houses, the lower house is called the House of Representatives and the upper house is named the Senate. The lower house currently consists of 150 members, each elected from single member constituencies, known as electoral divisions (commonly referred to as "electorates" or "seats") using full-preference Instant-runoff voting. This tends to lead to the chamber being dominated by two major parties, the Liberal/National Coalition and the Labor Party. The government of the day must achieve the confidence of this House to gain and hold power.

text: The upper house, the Senate, is also popularly elected under the single transferable vote system of proportional representation. There are a total of 76 senators: 12 senators are elected from each of the six Australian states (regardless of population) and two from each of the two autonomous internal territories (the Australian Capital Territory and the Northern Territory).

text: Unlike upper houses in most Westminster parliamentary systems, the Australian Senate is vested with significant power, including the capacity to block legislation initiated by the government in the House of Representatives, making it a distinctive hybrid of British Westminster bicameralism and US-style bicameralism. As a result of proportional representation, the chamber features a multitude of parties vying for power. The governing party or coalition, which must maintain the confidence of the lower house, rarely has a majority in the Senate and usually needs to negotiate with other parties and Independents to get legislation passed.[8]

text: Others[edit]

text: In the German, Indian, and Pakistani systems, the upper houses (the Bundesrat, the Rajya Sabha, and the Senate respectively) are even more closely linked with the federal system, being appointed or elected directly by the governments or legislatures of each German or Indian state, or Pakistani province. This was also the case in the United States before the Seventeenth Amendment was adopted. Because of this coupling to the executive branch, German legal doctrine does not treat the Bundesrat as the second chamber of a bicameral system formally. Rather, it sees the Bundesrat and the Bundestag as independent constitutional bodies. Only the directly elected Bundestag is considered the parliament.[9] In the German Bundesrat, the various Länder have between three and six votes; thus, while the less populated states have a lower weight, they still have a stronger voting power than would be the case in a system based purely on population, as the most populous Land currently has about 27 times the population of the least populous. The Indian Upper House does not have the states represented equally, but on the basis of their population.

text: There is also bicameralism in countries that are not federations, but have upper houses with representation on a territorial basis. For example, in South Africa, the National Council of Provinces (and before 1997, the Senate) has its members chosen by each Province's legislature.

text: In Spain the Senate functions as a de facto territorial-based upper house, and there has been some pressure from the Autonomous Communities to reform it into a strictly territorial chamber.

text: The European Union maintains a bicameral legislative system consisting of the European Parliament, which is elected in general elections on the basis of universal suffrage, and the Council of the European Union, which consists of members of the governments of the Member States who are competent for a relevant field of legislation. The European Union is not considered a state, but it enjoys the power to legislate in many areas, with exclusive power in some areas.

text: Aristocratic and post-aristocratic[edit]

text: In a few countries, bicameralism involves the juxtaposition of democratic and aristocratic elements.

text: The best known example is the British House of Lords, which includes a number of hereditary peers. The House of Lords is a vestige of the aristocratic system that once predominated in British politics, while the other house, the House of Commons, is entirely elected. Over the years, some have proposed reforms to the House of Lords, some of which have been at least partly successful. The House of Lords Act 1999 limited the number of hereditary peers (as opposed to life peers, appointed by Her Majesty on the advice of the Prime Minister ) to 92, down from around 700. Of these 92, one is the Earl Marshal, a hereditary office always held by the Duke of Norfolk, one is the Lord Great Chamberlain, a hereditary office held by turns, currently by the Marquess of Cholmondeley, and the other 90 are elected by all sitting peers. Hereditary peers elected by the House to sit as representative peers sit for life; when a representative peer dies, byelections occur to fill the vacancy. The ability of the House of Lords to block legislation is curtailed by the Parliament Acts 1911 and 1949. Peers can introduce bills except Money Bills, and all legislation must be passed by both Houses of Parliament. If not passed within two sessions, the House of Commons can override the Lords delay by invoking the Parliament Act. Certain legislation, however, must be approved by both Houses and can't be forced through by the Commons under the Parliament Act. These include any bill that would extend the time length of a Parliament, private bills, bills sent to the House of Lords less than one month before the end of a session, and bills that originated in the House of Lords.

text: Life Peers are appointed either by recommendation of the Appointment Commission; the independent body that vets non-partisan peers, typically from academia, business or culture, or by Dissolution Honour, which takes place at the end of every Parliamentary term and leaving MPs may be offered a seat to keep their institutional memory. It is traditional to offer a peerage to every outgoing Speaker of the House of Commons.[10]

text: Further reform of the Lords has been proposed; however, reform is not supported by many. Members of the House of Lords all have an aristocratic title, or are from the Clergy. 26 Archbishops and Bishops of the Church of England sit as Lords Spiritual, being the Archbishop of Canterbury, Archbishop of York, the Bishop of London, the Bishop of Durham, the Bishop of Winchester and the next 21 longest-serving Bishops. It is usual that retiring Archbishops, and certain other Bishops, are appointed to the Crossbenches and given a life peerage. Until 2009, 12 Lords of Appeal in Ordinary sat in the House as the highest court in the land; they subsequently became justices of the newly created Supreme Court of the United Kingdom. At present, 786 people sit in the House of Lords, with 92 Hereditary, 26 being Bishops or Archbishops (the Lords Spiritual) and the rest being Life Peers. Membership is not fixed and decreases only on the death of a life peer.

text: Another example of aristocratic bicameralism was the Japanese House of Peers, abolished after World War II and replaced with the present House of Councillors.

text: Unitary states[edit]

text: Many bicameral countries like the Netherlands, the Philippines, the Czech Republic, the Republic of Ireland and Romania are examples of bicameral systems existing in unitary states. In countries such as these, the upper house generally focuses on scrutinizing and possibly vetoing the decisions of the lower house.

text: On the other hand, in Italy the Parliament consists of two chambers that have the same role and power: the Senate (Senate of the Republic, commonly considered the upper house) and the Chamber of Deputies (considered the lower house).

text: In some of these countries, the upper house is indirectly elected. Members of France's Senate, Ireland's Seanad Éireann are chosen by electoral colleges consisting of members of the lower house, local councillors, the Taoiseach, and graduates of selected universities, while the Netherlands' Senate is chosen by members of provincial assemblies (which, in turn, are directly elected).

text: Norway had a kind of semi-bicameral legislature with two chambers, or departments, within the same elected body, the Storting. These were called the Odelsting and were abolished after the general election of 2009. According to Morten Søberg, there was a related system in the 1798 constitution of the Batavian Republic.[11]

text: In Hong Kong, members of the unicameral Legislative Council returned from the democratically elected geographical constituencies and partially-democratic functional constituencies are required to vote separately since 1997 on motions, bills or amendments to government bills not introduced by the government. The passage of these motions, bills or amendments to government bills requires double majority in both groups simultaneously. (Before 2004, when elections to the Legislative Council from the Election Committee was abolished, members returned through the Election Committee vote with members returned from geographical constituencies.) The double majority requirement does not apply to motions, bills and amendments introduced by the government.

text: Subnational entities[edit]

text: In some countries with federal systems, individual states (like those of the United States, Australia and a few States of India) may also have bicameral legislatures. Only three such states, Nebraska in the U.S., Queensland in Australia and Bavaria in Germany have later adopted unicameral systems. Brazilian states and Canadian provinces had all their upper houses abolished.

text: Argentina[edit]

text: In Argentina, eight provinces have bicameral legislatures, with a Senate and a Chamber of Deputies: Buenos Aires, Catamarca, Corrientes, Entre Ríos, Mendoza, Salta, San Luis (since 1987) and Santa Fe. Tucumán and Córdoba changed to unicameral systems in 1990 and 2001 respectively.

text: Australia[edit]

text: In Australian states, the lower house was traditionally elected based on the one-vote-one-value principle, whereas the upper house was partially appointed and elected, with a bias towards country voters and landowners. In Queensland, the appointed upper house was abolished in 1922, while in New South Wales there were similar attempts at abolition, before the upper house was reformed in the 1970s to provide for direct election. Nowadays, the upper house both federally and in most states is elected using the Single transferable vote form of proportional representation while the lower house uses Instant-runoff voting in single member electorates. This is reversed in the state of Tasmania, where proportional representation is used for the lower house and single member electorates for the upper house.

text: Bosnia and Herzegovina[edit]

text: The Legislature of the Federation of Bosnia and Herzegovina, one of the two entities of Bosnia and Herzegovina, is a bicameral legislative body. It consists of two chambers. The House of Representatives has 98 delegates, elected for four-year terms by proportional representation. The House of Peoples has 58 members, 17 delegates from among each of the constituent peoples of the Federation, and 7 delegates from among the other peoples.[12] Republika Srpska, the other entity, has a unicameral parliament, known as the National Assembly.[13]

text: Germany[edit]

text: The German federal state of Bavaria had a bicameral legislature from 1946 to 1999, when the Senate was abolished by a referendum amending the state's constitution. The other 15 states have used a unicameral system since their founding.

text: India[edit]

text: Seven Indian States, Andhra Pradesh, Telangana, Bihar, Jammu-Kashmir, Karnataka, Maharashtra and Uttar Pradesh, have bicameral Legislatures, these are called legislative councils (Vidhan Parishad), one third of whom are elected every two years, there are graduate constituencies (members elected exclusively by graduates), teachers constituencies (members elected exclusively by teachers), municipal constituencies (members elected exclusively by Mayors and council members of the city Governments). From 1956 to 1958 the Andhra Pradesh Legislature was unicameral. In 1958, when the Legislative Council was formed, it became bicameral until 1 June 1985 when it was abolished. This continued until March 2007 when the Legislative Council was reestablished and elections were held for its seats. Since then the Andhra Pradesh Legislature has become once again bicameral. In Tamil Nadu, a resolution was passed on 14 May 1986 and the Legislative Council was dissolved on 1 November 1986. Again on 12 April 2010, a resolution was passed to bring it back bicameral, but became unsuccessful in 2011.

text: Russia[edit]

text: Under Soviet regime regional and local Soviets were unicameral. After the adoption of 1993 Russian Constitution bicameralism was introduced in some regions. Bicameral regional legislatures are still technically allowed by federal law but this clause is dormant now. The last region to switch from bicameralism to unicameralism was Sverdlovsk Oblast in 2012.

text: United States[edit]

text: During the 1930s, the Legislature of the State of Nebraska was reduced from bicameral to unicameral with the 43 members that once comprised that state's Senate. One of the arguments used to sell the idea at the time to Nebraska voters was that by adopting a unicameral system, the perceived evils of the "conference committee" process would be eliminated.

text: A conference committee is appointed when the two chambers cannot agree on the same wording of a proposal, and consists of a small number of legislators from each chamber. This tends to place much power in the hands of only a small number of legislators. Whatever legislation, if any, the conference committee finalizes must then be approved in an unamendable "take-it-or-leave-it" manner by both chambers.

text: During his term as Governor of the State of Minnesota, Jesse Ventura proposed converting the Minnesotan legislature to a single chamber with proportional representation, as a reform that he felt would solve many legislative difficulties and impinge upon legislative corruption. In his book on political issues, Do I Stand Alone?, Ventura argued that bicameral legislatures for provincial and local areas were excessive and unnecessary, and discussed unicameralism as a reform that could address many legislative and budgetary problems for states.

text: Reform[edit]

text: Arab political reform[edit]

text: A 2005 report[14] on democratic reform in the Arab world by the U.S. Council on Foreign Relations co-sponsored by former Secretary of State Madeleine Albright urged Arab states to adopt bicameralism, with upper chambers appointed on a 'specialized basis'. The Council claimed that this would protect against the 'Tyranny of the majority', expressing concerns that without a system of checks and balances extremists would use the single chamber parliaments to restrict the rights of minority groups.

text: In 2002, Bahrain adopted a bicameral system with an elected lower chamber and an appointed upper house. This led to a boycott of parliamentary elections that year by the Al Wefaq party, who said that the government would use the upper house to veto their plans. Many secular critics of bicameralism were won around to its benefits in 2005, after many MPs in the lower house voted for the introduction of so-called morality police.

text: Romania[edit]

text: A referendum on introducing a unicameral Parliament instead of the current bicameral Parliament was held in Romania on 22 November 2009. The turnout rate was 50.95%, with 77.78% of "Yes" votes for a unicameral Parliament.[15] This referendum had a consultative role, thus requiring a parliamentary initiative and another referendum to ratify the new proposed changes.

text: Ivory Coast[edit]

text: A referendum on a new constitution was held on 30 October 2016. The constitution draft would create a bicameral Parliament instead of the current unicameral. The Senate is expected to represent the interests of territorial collectivities and Ivoirians living abroad. Two thirds of the Senate is to be elected at the same time as the general election. The remaining one third is appointed by the president elect.[16]

text: Examples[edit]

text: Current[edit]

text:
Country
Bicameral body
Notes

Upper house
Lower house

 Afghanistan
National Assembly

Masharano Jirga (House of Elders)
Wolesi Jirga (National Assembly)

 Algeria
Parliament

Council of the Nation
People's National Assembly

 Antigua and Barbuda
Parliament

Senate
House of Representatives

 Argentina
National Congress
Of the twenty-three provincial legislatures, eight are bicameral, while the remaining fifteen and the legislature of the Autonomous City of Buenos Aires are unicameral.

Senate
Chamber of Deputies

 Australia
Parliament
All of the state parliaments except Queensland's are also bicameral. The Northern Territory and the Australian Capital Territory are also unicameral.

Senate
House of Representatives

 Austria
Parliament
All of the Bundesländer have unicameral parliaments.

Bundesrat (Federal Council)
Nationalrat (National Council)

 Bahamas
Parliament

Senate
House of Assembly

 Bahrain
National Assembly

Consultative Council
Council of Representatives

 Barbados
Parliament

Senate
House of Assembly

 Belarus
National Assembly

Council
House of Representatives

 Belgium
Federal Parliament
All of the community and regional parliaments are unicameral.

Senate
Chamber of Representatives

 Belize
National Assembly

Senate
House of Representatives

 Bhutan
Parliament

National Council
National Assembly

 Bolivia
Plurinational Legislative Assembly

Senate
Chamber of Deputies

 Brazil
National Congress
All of the 26 state legislatures and the Federal District legislature are unicameral.

Senate
Chamber of Deputies

 Burundi
Parliament

Senate
National Assembly

 Cambodia
Parliament

Senate
National Assembly

 Canada
Parliament
All of the provincial legislatures are unicameral.

Senate
House of Commons

 Cameroon
Parliament

Senate
National Assembly

 Central African Republic
Parliament

Senate
National Assembly

 Chile
National Congress

Senate
Chamber of Deputies

 Colombia
Congress

Senate
Chamber of Representatives

 Czech Republic
Parliament

Senate
Chamber of Deputies

 DR Congo
Parliament

Senate
National Assembly

 Congo
Parliament

Senate
National Assembly

 Equatorial Guinea
Parliament

Senate
National Assembly

 Ethiopia
Federal Parliamentary Assembly
Regional Councils are unicameral. Assemblyman of the Regional Councils are elected directly.

House of Federation
House of Peoples' Representatives

 France
Parliament in the Fifth French Republic

Senate
National Assembly

 Gabon
Parliament

Senate
National Assembly

 Germany
N/A
In Germany, the chambers form two distinct constitutional bodies not framed by a comprehensive institution. All of the federal states (Länder) today have unicameral parliaments.

Bundesrat (Federal Council)
Bundestag (Federal Diet)

 Grenada
Parliament

Senate
House of Representatives

 Haiti
Parliament

Senate
Chamber of Deputies

 India
Parliament
Some of the states also have bicameral legislatures namely Vidhan Sabha (Legislative Assembly) and Vidhan Parishad (Legislative Council).

Rajya Sabha (Council of States)
Lok Sabha (House of the People)

 Indonesia
People's Consultative Assembly

Regional Representative Council
People's Representative Council

 Ireland
Oireachtas

Seanad Éireann (Senate of Ireland)
Dáil Éireann (Assembly of Ireland)

 Italy
Parliament

Senate of the Republic
Chamber of Deputies

 Ivory Coast
Parliament

Senate
National Assembly

 Jamaica
Parliament

Senate
House of Representatives

 Japan
National Diet

House of Councillors
House of Representatives

 Jordan
Parliament

Senate
House of Representatives

 Kazakhstan
Parliament

Senate
Majilis (Assembly of People)

 Kenya
Parliament

Senate
National Assembly

 Lesotho
Parliament

Senate
National Assembly

 Liberia
Legislature

Senate
House of Representatives

 Madagascar
Parliament

Senate
National Assembly

 Malaysia
Parliament
All the 13 State Legislative Assemblies are unicameral.

Dewan Negara (Senate)
Dewan Rakyat (House of Representatives)

 Mexico
Congress
All the 31 State Congresses and the Legislative Assembly of the Federal District are unicameral.

Senate
Chamber of Deputies

 Myanmar
Pyidaungsu Hluttaw (Assembly of the Union)
All the 14 State and Region Hluttaw (Assemblies) are unicameral.

Amyotha Hluttaw (House of Nationalities)
Pyithu Hluttaw (House of Representatives)

   Nepal
Parliament
[17]

Pratinidhi Sabha (House of Representatives)
Rashtriya Sabha (National Assembly)

 Netherlands
States General

Eerste Kamer
Tweede Kamer

 Nigeria
National Assembly

Senate
House of Representatives

 Oman
Parliament

Majlis al-Dawla (Council of State)
Majlis al-Shura (Consultative Assembly)

 Pakistan
Parliament
All of the provincial assemblies are unicameral.

Senate
National Assembly

 Palau
National Congress

Senate
House of Delegates

 Philippines
Congress
All local legislatures are unicameral.

Senate
House of Representatives

 Poland
National Assembly

Senate
Sejm (Diet)

 Romania
Parliament

Senate
Chamber of Deputies

 Russian Federation
Federal Assembly
All the regional legislatures are now unicameral while bicameralism in regions is technically allowed by the Federation.

Federation Council
State Duma

 Saint Lucia
Parliament

Senate
House of Assembly

 South Africa
Parliament
All of the provincial legislatures are unicameral.

National Council of Provinces
National Assembly

 Spain
Cortes Generales
Moreover, each Spanish autonomous region has its own unicameral regional parliament, with wide-ranging legislative powers on their own.

Senate
Congress of Deputies

  Switzerland
Federal Assembly
All of the cantons have unicameral parliaments.

Council of States
National Council

 United Kingdom
Parliament
Scotland, Wales and Northern Ireland have devolved unicameral legislatures with limited devolved powers.

House of Lords
House of Commons

 United States
Congress
All of the state legislatures, except Nebraska, are also bicameral. The Legislative Assembly of Puerto Rico is bicameral. The Council of the District of Columbia is unicameral.

Senate
House of Representatives

 Trinidad and Tobago
Parliament

Senate
House of Representatives

 Uruguay
General Assembly

Senate
Chamber of Representatives

 Uzbekistan
Supreme Assembly

Senate
Legislative Chamber

 Zimbabwe
Parliament

Senate
House of Assembly

tag: table

text: Historical[edit]

text:
Denmark
Rigsdagen
Under the constitution Rigsdagen was created, with two houses, an upper and lower house. However, after the 1953 referendum, both Rigsdagen and the Landsting was abolished, making the Folketing the sole chamber of the parliament.

Landsting (Upper house)
Folketing (Lower house)

 Greece
Parliament of the Hellenes
The Senate as an upper chamber was established by the Greek Constitution of 1844, of the Kingdom of Greece, and was abolished by the Greek Constitution of 1864. The Senate was reestabished by the republican Constitution of 1927, which establishing the Second Hellenic Republic and was disestablished by the restoration of the Kingdom of Greece at 1935.

Gerousia (Senate)
Vouli (Chamber of Deputies)

 Korea, South
National Assembly
Under the first constitution (first republic, 1948–52), the National Assembly was unicameral. The second and third constitutions (first republic, 1952–60) regulated the National Assembly was bicameral and consisted of the House of Commons and the Senate, but only the House of Commons was established and the House of Commons could not pass a bill to establish the Senate. During the short-lived second republic (1960–61), the National Assembly became practically bicameral, but it was overturned by the May 16 coup. The National Assembly has been unicameral since its reopen in 1963.

Senate
House of Commons

 New Zealand
Parliament
Until 1950, the New Zealand Parliament was bicameral. It became unicameral in 1951, but the name "House of Representatives" has been retained.

Legislative Council
House of Representatives

 Peru
Congress
Under the 1993 constitution, the bicameral system was replaced by the unicameral Congress of the Republic.

Senate
Chamber of Deputies

 Portugal
Cortes
During the period of Constitutional Monarchy, the Portuguese Parliament was bicameral. The lower house was the Chamber of Deputies and the upper house was the Chamber of Peers (except during the 1838-1842 period, where a Senate existed instead). With the replacement of the Monarchy by the Republic in 1910, the Parliament continued to be bicameral with a Chamber of Deputies and a Senate existing until 1926.

Chamber of Deputies
Chamber of Peers

 Sweden
Riksdagen
Until 1970, the Swedish Riksdag was bicameral. It became unicameral in 1971, but retained the name Riksdag.

Första kammaren (Upper house)
Andra kammaren (Lower house)

 Turkey
Parliament
It was established with the Turkish constitution of 1961 and abolished with the Turkish constitution of 1982, although it did not exist between 1980 and 1982 either as a result of the 1980 coup d'état in Turkey.

National Assembly
Senate of the Republic

 Venezuela
Congress
Under the 1999 constitution, the bicameral system was replaced by the unicameral National Assembly of Venezuela.

Chamber of Deputies
Senate

 Mauritania
Parliament
Under the 2017 Referendum, the bicameral system was replaced by the unicameral system.

Senate
National Assembly


document_title: Serotonin

question_text: where is serotonin released from in the brain

text: Serotonin

text: Functions[edit]

text: Serotonin is a neurotransmitter and is found in all bilateral animals including insects.[18] Serotonin is also present in plants (phytoserotonin).[19]

text: Perception of resource availability[edit]

text: Serotonin mediates the animal's perceptions of resource; In less complex animals, such as some invertebrates, resources simply mean food availability.[20] In plants serotonin synthesis seems to be associated with stress signals.[19] In more complex animals, such as arthropods and vertebrates, resources also can mean social dominance.[21] In response to the perceived abundance or scarcity of resources, an animal's growth, reproduction or mood may be elevated or lowered. This may somewhat depend on how much serotonin the organism has at its disposal.[citation needed]

text: Cellular effects[edit]

text: Receptors[edit]

text: The 5-HT receptors, the receptors for serotonin, are located on the cell membrane of nerve cells and other cell types in animals, and mediate the effects of serotonin as the endogenous ligand and of a broad range of pharmaceutical and hallucinogenic drugs. Except for the 5-HT3 receptor, a ligand-gated ion channel, all other 5-HT receptors are G-protein-coupled receptors (also called seven-transmembrane, or heptahelical receptors) that activate an intracellular second messenger cascade.[22]

text: Termination[edit]

text: Serotonergic action is terminated primarily via uptake of 5-HT from the synapse. This is accomplished through the specific monoamine transporter for 5-HT, SERT, on the presynaptic neuron. Various agents can inhibit 5-HT reuptake, including cocaine, dextromethorphan (an antitussive), tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs). A 2006 study conducted by the University of Washington suggested that a newly discovered monoamine transporter, known as PMAT, may account for "a significant percentage of 5-HT clearance".[23]

text: Contrasting with the high-affinity SERT, the PMAT has been identified as a low-affinity transporter, with an apparent Km of 114 micromoles/l for serotonin; approximately 230 times higher than that of SERT. However, the PMAT, despite its relatively low serotonergic affinity, has a considerably higher transport 'capacity' than SERT, "resulting in roughly comparable uptake efficiencies to SERT in heterologous expression systems."[this quote needs a citation] The study also suggests some SSRIs, such as fluoxetine and sertraline anti-depressants, inhibit PMAT but at IC50 values which surpass the therapeutic plasma concentrations by up to four orders of magnitude. Therefore, SSRI monotherapy is "ineffective" in PMAT inhibition. At present, no known pharmaceuticals are known to appreciably inhibit PMAT at normal therapeutic doses. The PMAT also suggestively transports dopamine and norepinephrine, albeit at Km values even higher than that of 5-HT (330–15,000 μmoles/L).[citation needed]

text: Serotonylation[edit]

text: Serotonin can also signal through a nonreceptor mechanism called serotonylation, in which serotonin modifies proteins.[24] This process underlies serotonin's effects upon platelet-forming cells (thrombocytes) in which it links to the modification of signaling enzymes called GTPases that then trigger the release of vesicle contents by exocytosis.[25] A similar process underlies the pancreatic release of insulin.[24]

text: The effects of serotonin upon vascular smooth muscle tone (this is the biological function from which serotonin originally got its name) depend upon the serotonylation of proteins involved in the contractile apparatus of muscle cells.[26]

text:
Binding profile of serotonin

Receptor
Ki (nM)[27]
Receptor function[Note 1]

5-HT1 receptor family signals via Gi/o inhibition of adenylyl cyclase.

5-HT1A
3.17
Memory[vague] (agonists ↓); learning[vague] (agonists ↓); anxiety (agonists ↓); depression (agonists ↓); positive, negative, and cognitive symptoms of schizophrenia (partial agonists ↓); analgesia (agonists ↑); aggression (agonists ↓); dopamine release in the prefrontal cortex (agonists ↑); serotonin release and synthesis (agonists ↓)

5-HT1B
4.32
Vasoconstriction (agonists ↑); aggression (agonists ↓); bone mass (↓). Serotonin autoreceptor.

5-HT1D
5.03
Vasoconstriction (agonists ↑)

5-HT1E
7.53

5-HT1F
10

5-HT2 receptor family signals via Gq activation of phospholipase C.

5-HT2A
11.55
Psychedelia (agonists ↑); depression (agonists & antagonists ↓); anxiety (antagonists ↓); positive and negative symptoms of schizophrenia (antagonists ↓); norepinephrine release from the locus coeruleus (antagonists ↑); glutamate release in the prefrontal cortex (agonists ↑); urinary bladder contractions (agonists ↑)[28]

5-HT2B
8.71
Cardiovascular functioning (agonists increase risk of pulmonary hypertension), empathy (via the spindle neurons or Von Economo neurons[29])

5-HT2C
5.02
Dopamine release into the mesocorticolimbic pathway (agonists ↓); acetylcholine release in the prefrontal cortex (agonists ↑); appetite (agonists ↓); antipsychotic effects (agonists ↑); antidepressant effects (agonists & antagonists ↑)

Other 5-HT receptors

5-HT3
593
Emesis (agonists ↑); anxiolysis (antagonists ↑).

5-HT4
125.89
Movement of food across the GI tract (agonists ↑); memory & learning (agonists ↑); antidepressant effects (agonists ↑). Signalling via Gαs activation of adenylyl cyclase.

5-HT5A
251.2
Memory consolidation.[30] Signals via Gi/o inhibition of adenylyl cyclase.

5-HT6
98.41
Cognition (antagonists ↑); antidepressant effects (agonists & antagonists ↑); anxiogenic effects (antagonists ↑[31]). Gs signalling via activating adenylyl cyclase.

5-HT7
8.11
Cognition (antagonists ↑); antidepressant effects (antagonists ↑). Acts by Gs signalling via activating adenylyl cyclase.

text: Nervous system[edit]

text: The neurons of the raphe nuclei are the principal source of 5-HT release in the brain.[32] There are nine raphe nuclei, designated B1-B9, which contain the majority of serotonin-containing neurons (some scientists chose to group the nuclei raphes lineares into one nucleus), all of which are located along the midline of the brainstem, and centered on the reticular formation.[33][34] Axons from the neurons of the raphe nuclei form a neurotransmitter system reaching almost every part of the central nervous system. Axons of neurons in the lower raphe nuclei terminate in the cerebellum and spinal cord, while the axons of the higher nuclei spread out in the entire brain.

text: Ultrastructure and Function[edit]

text: The serotonin nuclei may also be divided into two main groups, the rostral and caudal containing three and four nuclei respectively. The rostral group consists of the caudal linear nuclei (B8), the dorsal raphe nuclei (B6 and B7) and the median raphe nuclei (B5, B8 and B9), that project into multiple cortical and subcortical structures. The caudal group consists of the nucleus raphe magnus (B3), raphe obscurus nucleus (B2), raphe pallidus nucleus (B1), and lateral medullary reticular formation, that project into the brainstem.[35]

text: Serotonergic pathway are involved in sensorimotor function, with pathways projecting both into cortical (Dorsal and Median Raphe Nuclei), subcortical, and spinal areas involved in motor activity. Pharmacological manipulation suggest that serotonergic activity increases with motor activity, while firing rates of serotonergic neurons increase with intense visual stimuli. The descending projections form a pathway that inhibits pain called the "descending inhibitory pathway" that may be relevant to disorder such as fibromyalgia, migraine and other pain disorders, and the efficacy of antidepressants in them.[36]

text: Serotonergic projections from the caudal nuclei are involved in regulating mood, emotion and hypo[37] or hyperserotonergic[38] states may be involved in depression and sickness behavior.

text: Microanatomy[edit]

text: Serotonin is released into the synapse, or space between neurons, and diffuses over a relatively wide gap (>20 µm) to activate 5-HT receptors located on the dendrites, cell bodies and presynaptic terminals of adjacent neurons.

text: When humans smell food, dopamine is released to increase the appetite. But, unlike in worms, serotonin does not increase anticipatory behaviour in humans; instead, the serotonin released while consuming activates 5-HT2C receptors on dopamine-producing cells. This halts their dopamine release, and thereby serotonin decreases appetite. Drugs that block 5-HT2C receptors make the body unable to recognize when it is no longer hungry or otherwise in need of nutrients, and are associated with weight gain,[39] especially in people with a low number of receptors.[40] The expression of 5-HT2C receptors in the hippocampus follows a diurnal rhythm,[41] just as the serotonin release in the ventromedial nucleus, which is characterised by a peak at morning when the motivation to eat is strongest.[42]

text: The amount of food that an animal acquires depends not only on food availability but also on the animal's ability to compete with others. This is especially true for social animals, where the stronger individuals might steal food from the weaker (this is not to say some non-social animals do not concern themselves with the needs of others or steal food from others[citation needed]). Thus, serotonin is involved not only in the perception of food availability but also in social rank.

text: In macaques, alpha males have twice the level of serotonin released in the brain than subordinate males and females (as measured by the levels of 5-Hydroxyindoleacetic acid (5-HIAA) in the cerebro-spinal fluid). Dominance status and cerebro-serotonin levels appear to be positively correlated. When dominant males were removed from such groups, subordinate males begin competing for dominance. Once new dominance hierarchies were established, serotonin levels of the new dominant individuals also increased to double those in subordinate males and females. The reason why serotonin levels are only high in dominant males but not dominant females has not yet been established.[43]

text: In humans, levels of 5-HT1A receptor activation in the brain show negative correlation with aggression,[44] and a mutation in the gene that codes for the 5-HT2A receptor may double the risk of suicide for those with that genotype.[45] Serotonin in the brain is not usually degraded after use, but is collected by serotonergic neurons by serotonin transporters on their cell surfaces. Studies have revealed nearly 10% of total variance in anxiety-related personality depends on variations in the description of where, when and how many serotonin transporters the neurons should deploy.[46]

text: Psychological influences[edit]

text: Serotonin has been implicated in cognition, mood, anxiety and psychosis, but strong clarity has not been achieved.[47][48]

text: Outside the nervous system[edit]

text: In the digestive tract (emetic)[edit]

text: The gut is surrounded by enterochromaffin cells, which release serotonin in response to food in the lumen. This makes the gut contract around the food. Platelets in the veins draining the gut collect excess serotonin.

text: If irritants are present in the food, the enterochromaffin cells release more serotonin to make the gut move faster, i.e., to cause diarrhea, so the gut is emptied of the noxious substance. If serotonin is released in the blood faster than the platelets can absorb it, the level of free serotonin in the blood is increased. This activates 5-HT3 receptors in the chemoreceptor trigger zone that stimulate vomiting.[49] The enterochromaffin cells not only react to bad food but are also very sensitive to irradiation and cancer chemotherapy. Drugs that block 5HT3 are very effective in controlling the nausea and vomiting produced by cancer treatment, and are considered the gold standard for this purpose.[50]

text: Bone metabolism[edit]

text: In mice and humans, alterations in serotonin levels and signalling have been shown to regulate bone mass.[51][52][53][54] Mice that lack brain serotonin have osteopenia, while mice that lack gut serotonin have high bone density. In humans, increased blood serotonin levels have been shown to be significant negative predictor of low bone density. Serotonin can also be synthesized, albeit at very low levels, in the bone cells. It mediates its actions on bone cells using three different receptors. Through 5-HT1B receptors, it negatively regulates bone mass, while it does so positively through 5-HT2B receptors and 5-HT2C receptors. There is very delicate balance between physiological role of gut serotonin and its pathology. Increase in the extracellular content of serotonin results in a complex relay of signals in the osteoblasts culminating in FoxO1/ Creb and ATF4 dependent transcriptional events.[55] These studies have opened a new area of research in bone metabolism that can be potentially harnessed to treat bone mass disorders.[56]

text: Organ development[edit]

text: Since serotonin signals resource availability it is not surprising that it affects organ development. Many human and animal studies have shown that nutrition in early life can influence, in adulthood, such things as body fatness, blood lipids, blood pressure, atherosclerosis, behavior, learning and longevity.[57][58][59] Rodent experiment shows that neonatal exposure to SSRI's makes persistent changes in the serotonergic transmission of the brain resulting in behavioral changes,[60][61] which are reversed by treatment with antidepressants.[62] By treating normal and knockout mice lacking the serotonin transporter with fluoxetine scientists showed that normal emotional reactions in adulthood, like a short latency to escape foot shocks and inclination to explore new environments were dependent on active serotonin transporters during the neonatal period.[63][64]

text: Human serotonin can also act as a growth factor directly. Liver damage increases cellular expression of 5-HT2A and 5-HT2B receptors, mediating liver compensatory regrowth (see Liver § Regeneration and transplantation)[65] Serotonin present in the blood then stimulates cellular growth to repair liver damage.[66] 5HT2B receptors also activate osteocytes, which build up bone[67] However, serotonin also inhibits osteoblasts, through 5-HT1B receptors.[68]

text: Cardiovascular growth factor[edit]

text: Serotonin, in addition, evokes endothelial nitric oxide synthase activation and stimulates, through a 5-HT1B receptor-mediated mechanism, the phosphorylation of p44/p42 mitogen-activated protein kinase activation in bovine aortic endothelial cell cultures.[69] In blood, serotonin is collected from plasma by platelets, which store it. It is thus active wherever platelets bind in damaged tissue, as a vasoconstrictor to stop bleeding, and also as a fibrocyte mitotic (growth factor), to aid healing.[70]

text: Pharmacology[edit]

text: Several classes of drugs target the 5-HT system, including some antidepressants, antipsychotics, anxiolytics, antiemetics, and antimigraine drugs, as well as the psychedelic drugs and empathogens.

text: Psychedelic drugs[edit]

text: The psychedelic drugs psilocin/psilocybin, DMT, mescaline, psychedelic mushroom and LSD are agonists, primarily at 5HT2A/2C receptors.[71][72][73] The empathogen-entactogen MDMA releases serotonin from synaptic vesicles of neurons.[74]

text: Antidepressants[edit]

text: Drugs that alter serotonin levels are used in treating depression, generalized anxiety disorder and social phobia. Monoamine oxidase inhibitors (MAOIs) prevent the breakdown of monoamine neurotransmitters (including serotonin), and therefore increase concentrations of the neurotransmitter in the brain. MAOI therapy is associated with many adverse drug reactions, and patients are at risk of hypertensive emergency triggered by foods with high tyramine content, and certain drugs. Some drugs inhibit the re-uptake of serotonin, making it stay in the synaptic cleft longer. The tricyclic antidepressants (TCAs) inhibit the reuptake of both serotonin and norepinephrine. The newer selective serotonin reuptake inhibitors (SSRIs) have fewer side-effects and fewer interactions with other drugs.[75]

text: Certain SSRI medications have been shown to lower serotonin levels below the baseline after chronic use, despite initial increases.[76] The 5-HTTLPR gene codes for the number of serotonin transporters in the brain, with more serotonin transporters causing decreased duration and magnitude of serotonergic signaling.[77] The 5-HTTLPR polymorphism (l/l) causing more serotonin transporters to be formed is also found to be more resilient against depression and anxiety.[78][79]

text: Serotonin syndrome[edit]

text: Extremely high levels of serotonin can cause a condition known as serotonin syndrome, with toxic and potentially fatal effects. In practice, such toxic levels are essentially impossible to reach through an overdose of a single antidepressant drug, but require a combination of serotonergic agents, such as an SSRI with an MAOI.[80] The intensity of the symptoms of serotonin syndrome vary over a wide spectrum, and the milder forms are seen even at nontoxic levels.[81]

text: Antiemetics[edit]

text: Some 5-HT3 antagonists, such as ondansetron, granisetron, and tropisetron, are important antiemetic agents. They are particularly important in treating the nausea and vomiting that occur during anticancer chemotherapy using cytotoxic drugs. Another application is in the treatment of postoperative nausea and vomiting.

text: Other[edit]

text: Some serotonergic agonist drugs cause fibrosis anywhere in the body, particularly the syndrome of retroperitoneal fibrosis, as well as cardiac valve fibrosis.[82] In the past, three groups of serotonergic drugs have been epidemiologically linked with these syndromes. These are the serotonergic vasoconstrictive antimigraine drugs (ergotamine and methysergide),[82] the serotonergic appetite suppressant drugs (fenfluramine, chlorphentermine, and aminorex), and certain anti-Parkinsonian dopaminergic agonists, which also stimulate serotonergic 5-HT2B receptors. These include pergolide and cabergoline, but not the more dopamine-specific lisuride.[83]

text: As with fenfluramine, some of these drugs have been withdrawn from the market after groups taking them showed a statistical increase of one or more of the side effects described. An example is pergolide. The drug was declining in use since it was reported in 2003 to be associated with cardiac fibrosis.[84]

text: Two independent studies published in the New England Journal of Medicine in January 2007, implicated pergolide, along with cabergoline, in causing valvular heart disease.[85][86] As a result of this, the FDA removed pergolide from the United States market in March 2007.[87] (Since cabergoline is not approved in the United States for Parkinson's Disease, but for hyperprolactinemia, the drug remains on the market. Treatment for hyperprolactinemia requires lower doses than that for Parkinson's Disease, diminishing the risk of valvular heart disease).[88]

text: Methyl-tryptamines and hallucinogens[edit]

text: Several plants contain serotonin together with a family of related tryptamines that are methylated at the amino (NH2) and (OH) groups, are N-oxides, or miss the OH group. These compounds do reach the brain, although some portion of them are metabolized by monoamine oxidase enzymes (mainly MAO-A) in the liver. Examples are plants from the Anadenanthera genus that are used in the hallucinogenic yopo snuff. These compounds are widely present in the leaves of many plants, and may serve as deterrents for animal ingestion. Serotonin occurs in several mushrooms of the genus Panaeolus.[89]

text: Comparative biology and evolution[edit]

text: Unicellular organisms[edit]

text: Serotonin is used by a variety of single-cell organisms for various purposes. SSRIs have been found to be toxic to algae.[90] The gastrointestinal parasite Entamoeba histolytica secretes serotonin, causing a sustained secretory diarrhea in some people.[16][91] Patients infected with E. histolytica have been found to have highly elevated serum serotonin levels, which returned to normal following resolution of the infection.[92] E. histolytica also responds to the presence of serotonin by becoming more virulent.[93] This means serotonin secretion not only serves to increase the spread of enteamoebas by giving the host diarrhea but also serves to coordinate their behaviour according to their population density, a phenomenon known as quorum sensing. Outside the gut of a host, there is nothing that the entoamoebas provoke to release serotonin, hence the serotonin concentration is very low. Low serotonin signals to the entoamoebas they are outside a host and they become less virulent to conserve energy. When they enter a new host, they multiply in the gut, and become more virulent as the enterochromaffine cells get provoked by them and the serotonin concentration increases.

text: Plants[edit]

text: In drying seeds, serotonin production is a way to get rid of the buildup of poisonous ammonia. The ammonia is collected and placed in the indole part of L-tryptophan, which is then decarboxylated by tryptophan decarboxylase to give tryptamine, which is then hydroxylated by a cytochrome P450 monooxygenase, yielding serotonin.[94]

text: However, since serotonin is a major gastrointestinal tract modulator, it may be produced by plants in fruits as a way of speeding the passage of seeds through the digestive tract, in the same way as many well-known seed and fruit associated laxatives. Serotonin is found in mushrooms, fruits and vegetables. The highest values of 25–400 mg/kg have been found in nuts of the walnut (Juglans) and hickory (Carya) genera. Serotonin concentrations of 3–30 mg/kg have been found in plantains, pineapples, banana, kiwifruit, plums, and tomatoes. Moderate levels from 0.1–3 mg/kg have been found in a wide range of tested vegetables.[17]

text: Serotonin is one compound of the poison contained in stinging nettles (Urtica dioica), where it causes pain on injection in the same manner as its presence in insect venoms (see below). It is also naturally found in Paramuricea clavata, or the Red Sea Fan.[95]

text: Serotonin and tryptophan have been found in chocolate with varying cocoa contents. The highest serotonin content (2.93 µg/g) was found in chocolate with 85% cocoa, and the highest tryptophan content (13.27–13.34 µg/g) was found in 70–85% cocoa. The intermediate in the synthesis from tryptophan to serotonin, 5-hydroxytryptophan, was not found.[96]

text: Invertebrates[edit]

text: Serotonin functions as a neurotransmitter in the nervous systems of most animals. For example, in the roundworm Caenorhabditis elegans, which feeds on bacteria, serotonin is released as a signal in response to positive events, such as finding a new source of food or in male animals finding a female with which to mate.[97] When a well-fed worm feels bacteria on its cuticle, dopamine is released, which slows it down; if it is starved, serotonin also is released, which slows the animal down further. This mechanism increases the amount of time animals spend in the presence of food.[98] The released serotonin activates the muscles used for feeding, while octopamine suppresses them.[99] Serotonin diffuses to serotonin-sensitive neurons, which control the animal's perception of nutrient availability.

text: If lobsters are injected with serotonin, they behave like dominant individuals whereas octopamine causes subordinate behavior.[21] A crayfish that is frightened may flip its tail to flee, and the effect of serotonin on this behavior depends largely on the animal's social status. Serotonin inhibits the fleeing reaction in subordinates, but enhances it in socially dominant or isolated individuals. The reason for this is social experience alters the proportion between serotonin receptors (5-HT receptors) that have opposing effects on the fight-or-flight response.[clarification needed] The effect of 5-HT1 receptors predominates in subordinate animals, while 5-HT2 receptors predominates in dominants.[100]

text: Insects[edit]

text: Serotonin is evolutionary conserved and appears across the animal kingdom. It is seen in insect processes in roles similar to in the human central nervous system, such as memory, appetite, sleep, and behavior.[101][18] Locust swarming is mediated by serotonin, by transforming social preference from aversion to a gregarious state that enables coherent groups.[102] Learning in flies and honeybees is affected by the presence of serotonin.[103][104] Insect 5-HT receptors have similar sequences to the vertebrate versions, but pharmacological differences have been seen. Invertebrate drug response has been far less characterized than mammalian pharmacology and the potential for species selective insecticides has been discussed.[105]

text: Wasps and hornets have serotonin in their venom,[106] which causes pain and inflammation.[15] as do scorpions.[107]

text: If flies are fed serotonin, they are more aggressive; flies depleted of serotonin still exhibit aggression, but they do so much less frequently.[108]

text: Growth and reproduction[edit]

text: In the nematode C. elegans, artificial depletion of serotonin or the increase of octopamine cues behavior typical of a low-food environment: C. elegans becomes more active, and mating and egg-laying are suppressed, while the opposite occurs if serotonin is increased or octopamine is decreased in this animal.[20] Serotonin is necessary for normal nematode male mating behavior,[109] and the inclination to leave food to search for a mate.[110] The serotonergic signaling used to adapt the worm's behaviour to fast changes in the environment affects insulin-like signaling and the TGF beta signaling pathway,[111] which control long-term adaption.

text: In the fruit fly insulin both regulates blood sugar as well as acting as a growth factor. Thus, in the fruit fly, serotonergic neurons regulate the adult body size by affecting insulin secretion.[112][113] Serotonin has also been identified as the trigger for swarm behavior in locusts.[114] In humans, though insulin regulates blood sugar and IGF regulates growth, serotonin controls the release of both hormones, modulating insulin release from the beta cells in the pancreas through serotonylation of GTPase signaling proteins.[24] Exposure to SSRIs during Pregnancy reduces fetal growth.[115]

text: Genetically altered C. elegans worms that lack serotonin have an increased reproductive lifespan, may become obese, and sometimes present with arrested development at a dormant larval state.[116][117]

text: Aging and age-related phenotypes[edit]

text: Serotonin is known to regulate aging, learning and memory. The first evidence comes from the study of longevity in C. elegans.[118] During early phase of aging[vague], the level of serotonin increases, which alters locomotory behaviors and associative memory.[119] The effect is restored by mutations and drugs (including mianserin and methiothepin) that inhibit serotonin receptors. The observation does not contradict with the notion that the serotonin level goes down in mammals and humans, which is typically seen in late but not early[vague] phase of aging.

text: Biochemical mechanisms[edit]

text: Biosynthesis[edit]

text: In animals including humans, serotonin is synthesized from the amino acid L-tryptophan by a short metabolic pathway consisting of three enzymes: tryptophan hydroxylase (TPH), aromatic amino acid decarboxylase (DDC) and pyridoxal phosphate. The TPH-mediated reaction is the rate-limiting step in the pathway. TPH has been shown to exist in two forms: TPH1, found in several tissues, and TPH2, which is a neuron-specific isoform.[120]

text: Serotonin can be synthesized from tryptophan in the lab using Aspergillus niger and Psilocybe coprophila as catalysts. The first phase to 5-hydroxytryptophan would require letting tryptophan sit in ethanol and water for 7 days, then mixing in enough HCl (or other acid) to bring the pH to 3, and then adding NaOH to make a pH of 13 for 1 hour. Asperigillus niger would be the catalyst for this first phase. The second phase to synthesizing tryptophan itself from the 5-hydroxytryptophan intermediate would require adding ethanol and water, and letting sit for 30 days this time. The next two steps would be the same as the first phase: adding HCl to make the pH = 3, and then adding NaOH to make the pH very basic at 13 for 1 hour. This phase uses the Psilocybe coprophila as the catalyst for the reaction.[121]

text: Serotonin taken orally does not pass into the serotonergic pathways of the central nervous system, because it does not cross the blood–brain barrier.[122] However, tryptophan and its metabolite 5-hydroxytryptophan (5-HTP), from which serotonin is synthesized, does cross the blood–brain barrier. These agents are available as dietary supplements, and may be effective serotonergic agents. One product of serotonin breakdown is 5-hydroxyindoleacetic acid (5-HIAA), which is excreted in the urine. Serotonin and 5-HIAA are sometimes produced in excess amounts by certain tumors or cancers, and levels of these substances may be measured in the urine to test for these tumors.

text: Effects of food content[edit]

text: Consuming purified tryptophan increases brain serotonin whereas eating foods containing tryptophan does not.[123] This is because the transport system which brings tryptophan across the blood-brain barrier is also selective for the other amino acids contained in protein sources.[122] High plasma levels of other large neutral amino acids compete for transport and prevent the elevated plasma tryptophan from increasing serotonin synthesis.

text: History and etymology[edit]

text: In 1935, Italian Vittorio Erspamer showed an extract from enterochromaffin cells made intestines contract. Some believed it contained adrenaline, but two years later, Erspamer was able to show it was a previously unknown amine, which he named "enteramine".[124] In 1948, Maurice M. Rapport, Arda Green, and Irvine Page of the Cleveland Clinic discovered a vasoconstrictor substance in blood serum, and since it was a serum agent affecting vascular tone, they named it serotonin.[125]

text: In 1952, enteramine was shown to be the same substance as serotonin, and as the broad range of physiological roles was elucidated, the abbreviation 5-HT of the proper chemical name 5-hydroxytryptamine became the preferred name in the pharmacological field.[126] Synonyms of serotonin include: 5-hydroxytriptamine, thrombotin, enteramin, substance DS, and 3-(β-Aminoethyl)-5-hydroxyindole.[127] In 1953, Betty Twarog and Page discovered serotonin in the central nervous system.[128]