Biological effects Serotonin

Enterochromaffin cells are interspersed with mucosal cells mainly in the stomach and small intestine. In the blood, serotonin is present at high concentrations in platelets, which take up serotonin from the plasma by an active transport process. Serotonin is released on platelet activation. In the central nervous system, serotonin serves as a transmitter. The main serotonin-containing neurons are those clustered in form of the Raphe nuclei. Serotonin exerts its biological effects through the activation of specific receptors. Most of them are G-protein coupled receptors (GPCRs) and belong to the 5-HTr, 5-HT2-, 5-HT4-, 5-HTs-, 5-HT6-, 5-HT7-receptor subfamilies. The 5-HT3-receptor is a ligand-operated ion channel. 

It lias been proposed that the conformational flexibility of most open-chain nearohormoncs. such as acetylcholine, epinephrine. serotonin, histamine, and related physiologically active biomolecules, permits multiple biological effects to he produced by each molecule, by virtue of their ability to. 

The unusual flavonoid derivative kuwanon G, 30, is reported to lower blood pressure in rabbits when administered intravenously at a dose of l.Omg/kg of body weight (743). (-h)-Catechin [(-h)-cyanidan-3)ff-ol], 31, is remarkably bioactive. Among its recently reported biological effects are the following antianaphylactic (517), anticoagulant (569), antihepatotoxic (963), platelet aggregation inhibition (118), and serotonin secretion inhibition (100) effects. 

Arylpiperazines have immensely important effects on various and diverse biological targets, in particular on CNS receptors. In the case of serotonin (5-HT) receptors, compounds containing this arylpiperazine moiety represent the largest systematically studied class of 5-HTia receptor ligands [63]. Structural alterations within long-chain arylpiperazines (LCAPs) occur mainly at the two opposite ends of a molecule and have been described by many authors [64-71]. 

Berger. U. Grzanna, R. and Molliver, M.E. The neurotoxic effects of p-chloroamphetamine (PCA) in the rat brain are blocked by serotonin depletion. Twenty-First Meeting of the Swiss Societies for Experimental Biology. Abstract. Experientia, in press. 

Structure is also essential in complex biological molecules. A lot of medicines used for psychiatric illnesses such as depression rely on their ability to interact with certain proteins in the brain. For instance, a class of antidepressants—medications that alleviate the symptoms of depression—act on proteins involved with the collection (reuptake) of the chemical serotonin, and they are known as selective serotonin reuptake inhibitors (SSRIs). This class of antidepressants includes Prozac and Zoloft. Earlier medications were also effective and are still sometimes used though they produce a number of side effects, such as dietary problems. Although an SSRI can also generate potentially dangerous side effects, psychiatrists tend to observe these effects less often. (Brain chemistry is the subject of chapter 3.)... 

Whitaker-Azmitia PM, Azmitia EC Serotonin trophic factors in development, plasticity and aging, in Serotonin, Molecular Biology, Receptors and Eunctional Effects. Edited by Fozard JR, Saxena PR. Basel, Switzerland, Birkhauser Verlag, 1991, pp 43-49... 

Serotonin (4.109, 5-hydroxytryptamine, 5-HT) is a central neurotransmitter that is also found peripherally in the intestinal mucosa and in blood platelets, where its role is incompletely elucidated it even occurs in plants such as bananas. Although there is an enormous literature on the biochemistry and pharmacology of serotonin, our knowledge of its biological role remains somewhat fragmented. The diverse physiological effects of 5-HT influence the cardiovascular system, the cerebrovascular system, the digestive... 

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