reaction to osmotic stimulation and its regulation,” Brain Structure Function, 215, No
- M. A. Abramova, A. Calas, M. Ugrumov, “Vasopressinergic neurons of the supraoptic nucleus in perinatal rats
- 3–4, 195–207
One of the most important functions of the neuroendocrine system is that of regulating reproduction, particularly the inhibition of prolactin secretion in the hypophysis by dopamine (DA) synthesized in the arcuate nucleus. Apart from DA, noradrenaline (NA) also has a role in controlling prolactin secretion. While the role of DA in this regulation is known, that of NA remains incompletely understood. Previous studies have suggested that in conditions of functional insufficiency of the dopaminergic system, NA suppresses compensatory DA synthesis in the dopamine-producing neurons of the arcuate nucleus. The aim of the present work was to clarify the role of NA in the control of dopamine-producing neurons in the arcuate nucleus. This was addressed using two pharmacological models: 1) exclusion of dopaminergic and noradrenergic neurons and/or their axons in the arcuate nucleus, and b) exclusion of dopaminergic neurons only, to allow the role of the noradrenergic component to the catecholaminergic regulation of prolactin secretion to be assessed. In conditions of functional insufficiency of dopaminergic neurons, retention of the noradrenergic innervation of the arcuate nucleus was found to lead to decreased expression of the first enzyme in DA synthesis – tyrosine hydroxylase – and exacerbation of DA deficiency. This is evidence for noradrenergic inhibitory control of the expression of tyrosine hydroxylase in arcuate nucleus neurons.