adding because @ultimape ness
Nicholas Perry (@ultimape) tweeted at 10:01 AM – 5 Feb 2017 :
Makes sense if serotonin was a primordial chemical signal modulating social preferences, and it’s since been co-opted for many tasks. (http://twitter.com/ultimape/status/828287390078877696?s=17)
Nicholas Perry (@ultimape) tweeted at 9:58 AM – 5 Feb 2017 :
“women want to eat babies” => actually that serotonin + dopamine make us seek each other /forage. Food anticipation? https://t.co/P2rJxM6CNU (http://twitter.com/ultimape/status/828286784941486081?s=17)
Nicholas Perry (@ultimape) tweeted at 9:05 AM – 5 Feb 2017 :
Really weird how often serotonin, starvation, and behavior change show up. Also see in ants, bees, humans… https://t.co/SqJQ3942di (http://twitter.com/ultimape/status/828273278347259904?s=17)
Nicholas Perry (@ultimape) tweeted at 9:02 AM – 5 Feb 2017 :
“few hours crowding can induce this radical change in behavior, but can we break that down[?]” https://t.co/dwloo5kIZn (http://twitter.com/ultimape/status/828272503835521026?s=17)
Nicholas Perry (@ultimape) tweeted at 8:43 AM – 5 Feb 2017 :
“solitary and lonely creature, the desert locust. But just give them a little serotonin, and they go and join a gang https://t.co/AEhk9DezTs (http://twitter.com/ultimape/status/828267930257391622?s=17)
happens if crowded.. leg rubbing min # of times over 4 hour period
Serotonin (/ˌsɛrəˈtoʊnᵻn, ˌsɪərə–/) or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract (GI tract), blood platelets, and the central nervous system (CNS) of animals, including humans.
It is popularly thought to be a contributor to feelings of well-being and happiness.
Approximately 90% of the human body’s total serotonin is located in the enterochromaffin cells in the GI tract, where it is used to regulate intestinal movements. The serotonin is secreted luminally and basolaterally which leads to increased serotonin uptake by circulating platelets and activation after stimulation, which gives increased stimulation of myenteric neurons and gastrointestinal motility. The remainder is synthesized in serotonergic neurons of the CNS, where it has various functions. These include the regulation of mood, appetite, and sleep. Serotonin also has 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 eventually finds its way out of tissues into the blood. There, it is actively taken up by blood platelets, which store it. When the platelets bind to a clot, they release serotonin, where it serves as a vasoconstrictor and helps to regulate hemostasis and blood clotting. Serotonin also is a growth factor for some types of cells, which may give it a role in wound healing. There are various serotonin receptors.
Serotonin is metabolized mainly to 5-HIAA, chiefly by the liver. Metabolism involves first oxidation by monoamine oxidase to the corresponding aldehyde. This is followed by oxidation by aldehyde dehydrogenase to 5-HIAA, the indole acetic acid derivative. The latter is then excreted by the kidneys.
In addition to animals, serotonin is found in fungi and plants. 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 amoebae, 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
Pharmacological manipulation suggest that serotonergic activity increases with motor activity, while firing rates of serotonergic neurons increase with intense visual stimuli. ….Serotonergic projections from the caudal nuclei are involved in regulating mood, emotion and hypo or hyperserotonergic states may be involved in depression and sickness behavior.
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 increased weight gain, especially in people with a low number of receptors. The expression of 5-HT2Creceptors in the hippocampus follows a diurnal rhythm, just as the serotonin release in the ventromedial nucleus, which is characterised by a peak at morning when the motivation to eat is strongest.
How much food an animal gets not only depends on food availability but also depends 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). Thus, serotonin is not only involved in the perception of food availability but also involved in social rank.
The reason why serotonin levels are only high in dominant males but not dominant females has not yet been established.
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. 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
In mice and humans, alterations in serotonin levels and signalling have been shown to regulate bone mass. 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 densityv
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. ….. and inclination to explore new environments were dependent on active serotonin transporters during the neonatal period.
In humans, defective signaling of serotonin in the brain may be the root cause of sudden infant death syndrome (SIDS).
Serotonin is found in mushrooms, fruits and vegetables. .. plantains, pineapples, banana, kiwifruit, plums, and tomatoes. …..chocolate with varying cocoa contents.
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. The released serotonin activates the muscles used for feeding, while octopamine suppresses them. Serotonin diffuses to serotonin-sensitive neurons, which control the animal’s perception of nutrient availability.
…Serotonin inhibits the fleeing reaction in subordinates, but enhances it in socially dominant or isolated individuals.
Locust swarming is mediated by serotonin, by transforming social preference from aversion to a gregarious state that enables coherent groups. Learning in flies and honeybees is affected by the presence of serotonin. ..Wasps and hornets have serotonin in their venom, as do scorpions…If flies are fed serotonin, they are more aggressive; flies depleted of serotonin still exhibit aggression, but they do so much less frequently.
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”. 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.
….In 1953, Betty Twarog and Page discovered serotonin in the central nervous system
Serotonin is an example of a neurotransmitter, a chemical messenger that is passed between nerve cells. When a nerve impulse reaches the axon at the end of a nerve, neurotransmitters are released which cross an area called the synapse to be received by a specific receptor on the end of a target nerve. Once received by the target nerve, the neurotransmitter may either excite that nerve to fire its own signal or prevent it from firing the signal
Medications that increase the availability and uptake of serotonin are used to treat depression.