This study is designed to examine the combined and separate roles of the aortic and carotid arterial baroreceptors in the regulation of arterial pressure in the subhuman primate (Papio anubis) and to determine if there is an interaction between the arterial baroreflexes with cardiopulmonary vagal afferents and renal-fluid regulatory mechanisms in the regulation of basal arterial pressure. Specific objectives are to determine the effects of partial and total arterial baroreceptor denervation on the 24-hour average arterial pressure and heart rate in the conscious baboon. In addition, we will determine the separate roles of the aortic and carotid baroreflexes in the reflex control of arterial pressure, plasma catecholamine and vasopressin concentrations. Finally, a major goal is to determine the factors responsible for the return of arterial pressure toward control levels following sinoaortic denervation. We postulate that two mechanisms, cardiopulmonary vagal afferents and renal-fluid regulatory mechanisms, act to prevent a sustained hypertension following sinoaortic deafferentation in the conscious baboon. To address the hypothesis, renal fluid and electrolyte balance studies and body fluid volume measurements will be performed before and periodically following sinoaortic deafferentation. Likewise, we will determine if the inhibitory influence of vagal afferents increase during the postdeafferentation period.
