Serotonin, or 5-oksitriptamin, on the chemical building belongs to group of indolylalkylamines. It is the biogenous amine which is formed in an organism as a result of L-tryptophane amino acid hydroxylation.
Serotonin contains in different bodies and fabrics, including in thrombocytes, enterokhromaffinny cells of intestines, in cells of a medulla of adrenal glands. In nervous system the biosynthesis of serotonin happens in cytoplasm of nerve terminations. It collects in synoptic bubbles, is allocated under the influence of nervous impulses and interacts with the specific receptors designated as serotoninovy (serotonergic). Serotoni new receptors contain also in peripheral fabrics.
In the past the serotoninovy receptors divided into the M-receptors blocked by morphine and the D-receptors blocked by phenoxybenzamine. Now other classification of these receptors according to which their main subtypes are 5-HT M 1 (5HT M1 - from words 5-Hydroxy Tryptophan, S - from Serotonine) (or S M1) - receptors, 5-HT M2 (or S M2) - receptors, 5-NTz (or Sz) - receptors is accepted.
5-НТ M2-Receptors contain in unstriated muscles of walls of vessels, in bronchial tubes and thrombocytes. 5-HT M1 - Receptors, perhaps, contain in smooth muscles of digestive tract. 5-HT M3 - Receptors contain in peripheral fabrics and in central nervous system.
Pharmacological effects of serotonin correlate mainly with excitement 5-HT M, 2 receptors.
The physiological role of serotonin is insufficiently studied. It plays a mediator role in central nervous system. The mechanism of action of a number of psychotropic drugs is connected with influence on serotonin biosynthesis, his metabolism and interaction with receptors. The big role is given to a serotonin role in pathogenesis of depressions and the mechanism of effect of antidepressants (see).
Believe that development of nausea and vomiting can be caused by stimulation serotoninovy 5-HT M3 - the receptors which are localized in the field of the emetic center.
Peripheral effect of serotonin is characterized by reduction of unstriated muscles of a uterus, intestines, bronchial tubes and other smooth muscle bodies, narrowing of blood vessels. It is one of inflammation mediators; renders at local (intracutaneous, hypodermic) use the significant edematous action. Has ability to shorten a bleeding time, to increase quantity of thrombocytes in peripheral blood, to increase aggregation of thrombocytes. At aggregation of thrombocytes from them serotonin is released.
As medicines serotonin and some of its derivatives and also some of his antagonists found application.