ROLE OF PERIPHERAL RECEPTORS IN INCREASED RELEASE OF VASOPRESSIN IN RESPONSE TO HEMORRHAGE

A reduction in blood volume is an effective stimulus for the release of vasopressin (ADH) from the neurohypophysls. It is widely held that the left atrial stretch receptors and carotid sinus baroreceptors mediate this response. In order to put this hypothesis to a definitive test, the stimulus of graded, serial hemorrhage was applied to anesthetized dogs in which these receptors were rendered inoperative. This was achieved by cutting the vagi and perfusing the carotid sinuses at constant mean and pulse pressures. The ability of these animals to respond to reduction in blood volume with an increase in the plasma titer of ADH was either absent or severely limited. It is concluded that receptors located in the carotid sinuses and receptors which have afferent nerve fibers in the vagi are of primary importance in the control of ADH release in response to hemorrhage.