Influence of Limbic System on Neurohypophysis

Abstract

The rate of release of the antidiuretic hormone (ADH) from the neurohypophysis into the hypophysial veins depends upon various factors, among which are osmotic pressure, blood volume, body temperature, and the emotional state. The supraoptic and paraventricular nuclei in the hypothalamus comprise the final common pathway activated by these afferent stimuli. However, the central neural mechanisms and pathways involved in the regulation of ADH release are not well understood. We have previously shown that the neurohypophysis can be influenced from the mesencephalic tegmentum,1a region which has important connections not only with the hypothalamus but also with the medial and basal regions of the forebrain.2The latter two areas, collectively termed the system,3have direct pathways to the hypothalamus4by which they influence somatovisceral5and endocrine functions.6Electrical excitation of parts of the limbic system has induced release of ovulating hormone,7corticotropin