Serotonin (pronounced /ˌsɛrəˈtəʊnɪn/) or 5-Hydroxytryptamine (5-HT) is a monoamine neurotransmitter Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group that is connected to an aromatic ring by a two-carbon chain . All monoamines are derived from aromatic amino acids like phenylalanine, tyrosine, tryptophan, and the thyroid hormones by the action of aromatic amino acid decarboxylase enzymes, biochemically derived from tryptophan Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG. Only the L-stereoisomer of tryptophan is used in structural or enzyme proteins, but the D-stereoisomer is occasionally found in naturally produced peptides (for example, the marine, that is primarily found in the gastrointestinal The Human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. (GI) tract, platelets Platelets, or thrombocytes , are small, irregularly-shaped anuclear cell fragments (i.e. cells that do not have a nucleus containing DNA), 2-3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days. Platelets play a fundamental role in hemostasis and are a, and central nervous system The central nervous system is the part of the nervous system that coordinates the activity of all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish. It contains the majority of the nervous system and consists of the brain and the spinal cord, as well as (CNS) of humans and animals. It is a well-known contributor to feelings of well-being.
Approximately 80 percent of the human body's total serotonin is located in the enterochromaffin cells Enterochromaffin cells (Kulchitsky cells) are a type of enteroendocrine cell occurring in the epithelia lining the lumen of the digestive tract and the respiratory tract in the gut, where it is used to regulate intestinal movements.[1][2] The remainder is synthesized in serotonergic Serotonergic or serotoninergic means "related to the neurotransmitter serotonin". A synapse is serotonergic if it uses serotonin as its neurotransmitter. A substance is serotonergic if it is capable of producing, altering, or releasing serotonin neurons A neuron (pronounced /ˈnjʊərɒn/ NOOR-on, also known as a neurone or nerve cell) is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core in the CNS where it has various functions, including the regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning. Modulation of serotonin at synapses is thought to be a major action of several classes of pharmacological antidepressants.
Serotonin secreted from the enterochromaffin cells Enterochromaffin cells (Kulchitsky cells) are a type of enteroendocrine cell occurring in the epithelia lining the lumen of the digestive tract and the respiratory tract eventually finds its way out of tissues into the blood. There, it is actively taken up by blood platelets Platelets, or thrombocytes , are small, irregularly-shaped anuclear cell fragments (i.e. cells that do not have a nucleus containing DNA), 2-3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days. Platelets play a fundamental role in hemostasis and are a, which store it. When the platelets bind to a clot, they disgorge serotonin, where it serves as a vasoconstrictor and helps to regulate hemostasis Hemostasis or haemostasis (from the Ancient Greek: αἱμόστασις haimóstasis "styptic ") is a complex process which causes the bleeding process to stop. It refers to the process of keeping blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). Most of the time this includes the changing of blood from a and blood clotting. Serotonin also is a growth factor for some types of cells, which may give it a role in wound healing.
Serotonin is eventually metabolized to 5-HIAA by the liver, and excreted by the kidneys. One type of tumor, called carcinoid Carcinoid is a slow-growing type of neuroendocrine tumour, originating in the cells of the neuroendocrine system, sometimes secretes large amounts of serotonin into the blood, which causes various forms of the carcinoid syndrome Carcinoid syndrome refers to the array of symptoms that occur secondary to carcinoid tumors of flushing, diarrhea, and heart problems. Because of serotonin's growth promoting effect on cardiac myocytes, persons with serotonin-secreting carcinoid may suffer a right heart (tricuspid) valve disease syndrome, caused by proliferation of myocytes onto the valve.
In addition to animals, serotonin is also found in fungi A fungus ) is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi (pronounced /ˈfʌndʒaɪ/ or /ˈfʌŋɡaɪ/), that is separate from plants, animals and bacteria. One major difference is that fungal and plants Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants, known as botany, has identified about 350,000 extant species of plants, defined as seed plants, bryophytes, ferns and fern allies. As of 2004,.[3] Serotonin's presence in insect venoms and plant spines serves to cause pain, which is a side effect of serotonin injection. Serotonin is produced by pathogenic amoebas, and its effect on the gut causes diarrhea. Its widespread presence in many seeds and fruits may serve to stimulate the digestive tract into expelling the seeds.
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History
In 1935, Italian Vittorio Erspamer showed that an extract from enterochromaffin cells made intestines contract. Some believed it contained adrenaline Epinephrine is a hormone and neurotransmitter.. It increases heart rate, contracts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. Chemically, epinephrine is a catecholamine, a monoamine produced only by the adrenal glands from the amino acids phenylalanine and tyrosine, but two years later Erspamer was able to show that it was a previously unknown amine Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines, trimethylamine, and aniline; see Category:Amines for, which he named enteramine.[4] In 1948, Maurice M. Rapport, Arda Green, and Irvine Page of the Cleveland Clinic The Cleveland Clinic is a multispecialty academic medical center located in Cleveland, Ohio, United States. The Cleveland Clinic is currently regarded as one of the top 4 hospitals in the United States. The Cleveland Clinic was established in 1921 by four physicians for the purpose of providing patient care, research, and medical education in an discovered a vasoconstrictor substance in blood serum Blood plasma is the yellow liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid(all body fluid outside of cells). It is mostly water (90% by volume) and contains dissolved proteins, glucose, clotting, and since it was a serum agent affecting vascular tone, they named it serotonin.[5] In 1952 it was shown that enteramine was the same substance as serotonin, and as the broad range of physiological roles were elucidated, the abbreviation 5HT of the proper chemical name 5-hydroxytryptamine became the preferred name in the pharmacological field.[6]
Functions
Serotonin is a neurotransmitter, and is found in all bilateral animals The bilateria are all animals having a bilateral symmetry, i.e. they have a front and a back end, as well as an upside and downside. Radially symmetrical animals like jellyfish have a topside and downside, but no front and back. The bilateralia are a subregnum (a major group) of animals, including the majority of phyla; the most notable exceptions where it mediates gut movements and the animal's perception of resource availability. In the simplest animals resources are equivalent with food, but in advanced animals such as arthropods An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the Phylum Arthropoda (from Greek ἄρθρον arthron, "joint", and ποδός podos "foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and and vertebrates Vertebrates are members of the subphylum Vertebrata, chordates with backbones and spinal columns. About 58,000 species of vertebrates have been currently described. Vertebrata is the largest subphylum of chordates, and contains many familiar groups of large land animals. Vertebrates are comprised of animals from the groups jawless fishs, bony fish, resources also can mean social dominance. In response to the perceived abundance or scarcity of resources the animal's growth, reproduction or mood A mood is a relatively long lasting emotional state. Moods differ from simple emotions in that they are less specific, less intense, and less likely to be triggered by a particular stimulus or event may be elevated or lowered. Recent studies involving the serotonin transporter gene 5-HTT have shown that the short allele of this gene increase synaptic serotonin levels. These genetic studies have demonstrated that serotonin has strong associations with depression in regards to a negative environment.
Gauge of food availability
Serotonin functions as a neurotransmitter in the nervous systems of simple as well as complex animals. For example, in the roundworm C. elegans Caenorhabditis elegans is a free-living, transparent nematode (roundworm), about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model organism, which feeds by grazing on bacteria, serotonin is released as a signal in response to positive events, e.g., finding a new grazing ground or in male animals finding a hermaphrodite to mate. When a well-fed worm feels bacteria on its cuticle A cuticle , or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Cuticles are non-homologous, differing in their origin, structure and chemical composition, dopamine Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors—D1, D2, D3, D4, and D5—and their variants. Dopamine is produced in several areas of the brain, 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.[7] The released serotonin activates the muscles used for feeding, while octopamine Octopamine, also known as β,4-dihydroxyphenethylamine, is an endogenous biogenic amine that is closely related to norepinephrine, and has effects on the adrenergic and dopaminergic systems. Biosynthesis of the D-enantiomer of octopamine is by β-hydroxylation of tyramine via the enzyme dopamine β-hydroxylase. Under the trade names Epirenor, suppresses them.[8] Serotonin diffuses to serotonin-sensitive neurons, which control the animal's perception of nutrient availability. This system has been partially conserved during the 700 million years of evolution which separate C. elegans from humans. 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 The 5-HT2C receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor (GPCR) that is coupled to Gq/G11 and mediates excitatory neurotransmission. HTR2C denotes the human gene encoding for the receptor on dopamine-producing cells. This halts their dopamine release, and thereby serotonin decreases appetite. Drugs which block 5-HT2C receptors make the body unable to shut off appetite, and are associated with increased weight gain,[9] especially in people who have a low number of receptors.[10] The expression of 5-HT2C receptors in the hippocampus follows a diurnal rhythm A circadian rhythm is a roughly 24-hour cycle in the biochemical, physiological, or behavioural processes of living entities, including plants, animals, fungi and cyanobacteria . The term "circadian" comes from the Latin circa, "around", and diem or dies, "day", meaning literally "approximately one day". The,[11] just as the serotonin release in the ventromedial nucleus, which is characterised by a peak at morning when the motivation to eat is strongest.[12]
Effects of food content
In humans, serotonin levels are affected by diet. An increase in the ratio of tryptophan to phenylalanine and leucine will increase serotonin levels. Fruits with a good ratio include dates, papaya and banana. Foods with a lower ratio inhibit the production of serotonin. These include whole wheat and rye bread.[13] Research also suggests that eating a diet rich in carbohydrates and low in protein will increase serotonin by secreting insulin, which helps in amino acid competition.[14] However, increasing insulin for a long period may trigger the onset of insulin resistance Insulin resistance is a physiological condition where the natural hormone, insulin, becomes less effective at lowering blood sugars. The resulting increase in blood glucose may raise levels outside the normal range and cause adverse health effects. Certain cell types such as fat and muscle cells require insulin to absorb glucose. When these cells, obesity Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Body mass index , a measurement which compares weight and height, defines people as overweight (pre-obese) when their BMI is between 25 kg/m2 and 30, type 2 diabetes Diabetes mellitus type 2 or type 2 diabetes (formerly called non -insulin-dependent diabetes mellitus , or adult-onset diabetes) is a disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and dietary modification. As the, and lower serotonin levels. Muscles use many of the amino acids except tryptophan, allowing men to have more serotonin than women.[15] Myo-inositol Inositol or cyclohexane-1,2,3,4,5,6-hexol is a chemical compound with formula C6H12O6 or 6, a sixfold alcohol (polyol) of cyclohexane. It exists in nine possible stereoisomers, of which the most prominent form, widely occurring in nature, is cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol[citation needed]. Inositol is a carbohydrate,, a carbocyclic polyol A polyol is an alcohol containing multiple hydroxyl groups. In two technological disciplines the term "polyol" has a special meaning: food science and polymer chemistry present in many foods, is known to play a role in serotonin modulation.[16]
In the digestive tract
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.
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 that 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 5HT3 receptors in the chemoreceptor trigger zone that stimulate vomiting Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure. The feeling that one is about to vomit is called nausea, which usually precedes, but does not always lead to,.[17] The enterochromaffin cells not only react to bad food, they are also very sensitive to irradiation Radiation therapy , or radiotherapy (in the UK and Australia) also called radiation oncology, and sometimes abbreviated to XRT, is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). Radiotherapy may be used for and cancer chemotherapy Chemotherapy, in its most general sense, is the treatment of a disease by chemicals especially by killing micro-organisms or cancerous cells. In popular usage, it refers to antineoplastic drugs used to treat cancer or the combination of these drugs into a cytotoxic standardized treatment regimen. In its non-oncological use, the term may also refer. Drugs that block 5HT3 The 5-HT3 antagonists are a class of medications that act as receptor antagonists at the 5-hydroxytryptamine-3 receptor , a subtype of serotonin receptor found in terminals of the vagus nerve and in certain areas of the brain. With the notable exception of alosetron and cilansetron, which are used in the treatment of irritable bowel syndrome, all 5 are very effective in controlling the nausea and vomiting produced by cancer treatment and are considered the gold standard for this purpose.[18]
Gauge of social situation
How much food an animal gets not only depends on the abundance of food, 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. Thus, serotonin is not only involved in the perception of food availability, but also of social rank. If a lobster Clawed lobsters comprise a family of large marine crustaceans. Lobsters are economically important as seafood, forming the basis of a global industry that nets more than US$1 billion annually is injected with serotonin, it behaves like a dominant animal In social animals, the alpha is the individual in the community with the highest rank. Where one male and one female fulfill this role, they are referred to as the alpha pair . Other animals in the same social group may exhibit deference or other symbolic signs of respect particular to their species towards the alpha, while octopamine Octopamine, also known as β,4-dihydroxyphenethylamine, is an endogenous biogenic amine that is closely related to norepinephrine, and has effects on the adrenergic and dopaminergic systems. Biosynthesis of the D-enantiomer of octopamine is by β-hydroxylation of tyramine via the enzyme dopamine β-hydroxylase. Under the trade names Epirenor, causes subordinate behavior.[19] A frightened crayfish Crayfish, crawfish, or crawdads — members of the superfamilies Astacoidea and Parastacoidea — are freshwater crustaceans resembling small lobsters, to which they are related. They breathe through feather-like gills and are found in bodies of water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is flips its tail to flee, and the effect of serotonin on this behavior depends 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 that social experience alters the proportion between serotonin receptors The serotonin receptors also known as 5-hydroxytryptamine receptors or 5-HT receptors are a group of G protein-coupled receptors and ligand-gated ion channels (LGICs) found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission. The serotonin receptors are activated by the neurotransmitter (5-HT receptors) that have opposing effects on the fight-or-flight response The "fight-or-flight response", also called the "fight-or-flight-or-freeze response", the "fright, fight or flight response", "hyperarousal" or the "acute stress response", was first described by Walter Cannon in 1929. The effect of 5-HT1 receptors predominates in subordinate animals while 5-HT2 receptors The 5-HT2 receptors are a subfamily of 5-HT receptors that bind the endogenous neurotransmitter serotonin . The 5-HT2 subfamily consists of three G-protein coupled receptors (GPCRs) which are coupled to Gq/G11 and mediate excitatory neurotransmission, including 5-HT2A, 5-HT2B, and 5-HT2C. For more information, please see the respective main predominates in dominants.[20] In humans, levels of 5-HT1A receptor activation in the brain show negative correlation with aggression,[21] and a mutation in the gene that codes for the 5-HT2A The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin (5-HT), although 5-HT2A may also have an inhibitory effect[citation needed] on certain areas such as the visual cortex and receptor may double the risk of suicide for those with that genotype.[22] Most of the brain serotonin is not degraded after use, but is collected by serotonergic neurons by serotonin transporters The serotonin transporter is a monoamine transporter protein on their cell surface. Studies have revealed that nearly 10% of total variance in anxiety-related personality depends on variations in the description of where, when and how many 5-HTTLPR is a degenerate repeat polymorphic region in SLC6A4, the gene that codes for the serotonin transporter. Since the polymorphism was identified in the middle of the 1990s, it has been extensively investigated, e.g., in connection with neuropsychiatric disorders. A 2006 scientific article stated that "over 300 behavioral, psychiatric, serotonin transporters the neurons should deploy,[23] and the effect of this variation was found to interact with the environment in depression.[24][25]
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Thu, 24 Jun 2010 21:20:29 GMT+00:00
Medscape June 24, 2010 Two new papers have raised red flags about visual problems linked to selective serotonin reuptake inhibitors (SSRIs) in elderly patients ...
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Twickenham foursome, Mystery Jets, unearth a refreshing taste of indie with brand new masterpiece . Serotonin. . After a two year break, the band's sound has somewhat matured since Twenty One and Making Dens, with . Serotonin. being the ...
Q. Was it the first serotonin reuptake inhibitor discovered?
Asked by B.B. - Thu Aug 13 20:55:32 2009 - - 2 Answers - 0 Comments
A. yeah, it was. serotonin functions as a neurotransmitter in nerve systems of simple as well as complex animals. The role of serotonin in animals with a more complex nerve system is in perceptions of more complex life situations such as, for example, social rank. If a lobster is injected with serotonin, it behaves like a dominant animal, while dopamine causes dominant behavior. Hope I helped =) Macy
Answered by Macy! stole ur main squeeze[: - Thu Aug 13 22:58:15 2009
