Serotonin og kardiovaskulaer kontrol

Serotonin is a monoamine and is widely distributed in the human organism. Serotonin is synthesized from the amino acid tryptophane and is broken down via mono-amino-oxydase enzymes to 5-hydroxy-indol-acetic acid and by acetylizing and methylizing to melantonin. In 1986, a consensus concerning the classification of the serotonergic receptors was established. Three main classes were determined, viz: 5-HT1, 5-HT2 and 5-HT3. 5-HT1 receptors were further subdivided into A, B, C and D-receptors and, of these, the 5-HT1A-receptor is involved in the centrally mediated blood pressure control via reduction in the pre- and postganglionic sympathetic activity. The 5-HT2 receptors are primarily involved in control of peripheral blood pressure where agonizing results in vascular contraction of the large arteries and veins and thrombocyte aggregation. The 5-HT1 receptors are also involved peripherally in connection with release of relaxing factors derived from endothelium. In vitro and in animal experiments, it has been demonstrated that serotonin is capable of inducing arrhythmia and myocardial dysfunction via 5-HT3 receptors. Several preparations with effects on both the central and peripheral serotonergic receptors are already marketed for treatment of hypertension and other conditions.