Serotonergic and Histaminergic Systems
Apart from the catecholamines, the most important of the biogenic amines presumed to have a neurotransmitter function are serotonin and histamine. Although the powerful vasoconstrictive action of serotonin (5-hydroxytryptamine or 5-HT) has been known for many years, it was not until 1964 that serotonergic neurons were first demonstrated in histochemical studies by Dahlstrom and Fuxe. The substance actually occurs widely in nature in both plants and animals. The greatest concentrations in mammals can be found in the enterochromaffin cells of the intestine and in the pineal gland. And, in relation to other organs of the body, the levels of 5-HT in the central nervous system are very low, comprising in man only about 1 to 2% of the whole body content.
KeywordsPineal Gland Raphe Nucleus Serotonergic Neuron Tryptophan Hydroxylase Medial Forebrain Bundle
Unable to display preview. Download preview PDF.