[The histaminergic brain neuron system].

This review describes the current concepts of distribution, morphological peculiarities and functions of histaminergic structures in human and animal brain. In adult mammals and humans, the perikarya of histaminergic neurons are localized exclusively in the hypothalamus, mainly in its tuberomamillary nuclei, where 5 subgroups are distinguished. It is only there that the syntheses of neuronal histamine takes place and histamine-synthesizing enzyme histidine decarboxylase and corresponding mRNA were found. The processes of histaminergic neurons innervate practically all the brain regions. Histamine action is mediated by three types of receptors: H1, H2 (postsynaptic) and H3 (presynaptic), which are widely distributed in the brain. Histaminergic brain system is involved in the regulation of various functions, systems and reactions of the organism and participates in the pathogeneses of many disturbances and diseases. The review provides the detailed description of the localization of histaminergic neuron perikarya in mammals, the existing classifications of histaminergic neurons of rat brain, the distribution of histaminergic fibers in various brain regions, the organization of human histaminergic brain system, histaminergic neuron ultrastructure, afferent innervation and regulation.