Differentiation of Magnocellular Vasopressinergic Neurons and Its Regulation by Signal Molecules in Ontogenesis

An analysis is presented of the literary data on differentiation of magnocellular vasopressinergic (VPergic) neurons and their regulation by signal molecules in ontogenesis. The VPergic neurons are formed in ontogenesis from cells-precursors of the III ventricle wall; after that, they migrate first into the supraoptic nucleus and then into the paraventricular and accessory nuclei of hypothalamus. At the migration period or at once after migration of the neurons a gene expression and synthesis of preprovasopressin (prepro-VP) occurs. The enzymatic processing of prepro-VP with a formation of functionally active VP begins somewhat later than synthesis of preprohormone. Axons of the VPergic neurons reach the posterior lobe of pituitary before or at once after migration of the neurons into the magnocellular nuclei. Much later, at the perinatal period, the mechanisms of VP release from axons into the general circulation are formed. At the end of prenatal period, the neurons start responding to functional stimulation by an increase of synthesis of the prepro-VP mRNA and peptide itself, as well as by expression of the tyrosine hydroxylase after birth. Differentiation of the VPergic neurons is affected by a short-term or long-term (imprinting) action of catecholamines, neuropeptides, and several hormones of endocrine glands.