Arterial pressure control after chronic carotid sinus denervation.

This study examines the control of arterial blood pressure in conscious, instrumented dogs with atrioventricular block before and greater than or equal to 9 days after carotid sinus baroreceptor denervation. Strength of reflex control of blood pressure was quantitated by measuring the changes in peripheral resistance and atrial rate after square wave changes in cardiac output. Surprisingly, nine or more days after carotid denervation, the strength of baroreflex control of peripheral resistance and atrial rate were not different (P greater than 0.05) from the values before denervation. This was not due to a change in the base-line levels of arterial pressure, atrial rate, cardiac output, or peripheral resistance. Bilateral vagal block after carotid denervation removed reflex effects from remaining baroreceptors and virtually eliminated changes in peripheral resistance in response to changes in arterial pressure. Therefore, the compensatory responses observed after carotid denervation were mediated by the remaining baroreceptors. Thus, after chronic carotid sinus denervation, there is no decrease in the strength of baroreflex control of peripheral resistance or heart rate.