Sino‐aortic denervation in the monkey.

The aortic arch and carotid sinuses were denervated in eleven monkeys. The monkeys were subjected to four sequential surgeries which involved: (1) implantation of an aortic and left atrial catheter; (2) stripping of the adventitia from the aortic arch; (3) stripping the left carotid sinus and associated vessels; and (4) stripping the right carotid sinus and associated vessels. Blood pressure and pulse rate were recorded 6 days after each surgical procedure. Records were taken over a 6 h period while the monkeys were in their home cages. Baroreceptor denervation was confirmed by: (1) absence of heart rate response to blood pressure changes and (2) an increase in the variability of blood pressure. Veratridine given into the left atrium caused a Bezold‐Jarisch reflex both before and after denervation verifying the integrity of the afferent and efferent vagus. Denervation of the baroreceptors resulted in a significant increase in blood pressure when measured from monkeys who were restrained in chairs in the laboratory; however, blood pressure was not significantly elevated in the baroreceptor denervated monkeys while they were tethered in their home cages. It is concluded that denervation of the sino‐aortic baroreceptor does not result in a significant increase in systemic blood pressure.