Reversible vascular isolation of carotid sinuses in conscious dogs

A surgical technique has been developed that permits reversible vascular isolation of both carotid sinuses in the conscious dog. Seven dogs so prepared were studied over periods of 4-12 wk. Repeatable stimulus-response curves relating arterial blood pressure to carotid sinus pressure were obtained for sinus pressures of 40-240 mmHg. Two studies gave evidence that the ability of the carotid baroreceptors to influence arterial pressure was not or was minimally affected by the surgical dissection. In 10 dogs one sinus was surgically prepared; 3 wk later the dogs were anesthetized and vagotomized. The steady-state stimulus-response curves for the chronically prepared sinuses showed no consistent differences from the curves for the opposite, acutely prepared sinuses. In 8 other dogs the hypertensive responses to bilateral carotid occlusion were compared before and after surgical preparation of both sinuses. The responses to carotid occlusion tended to be decreased after surgery but the differences were small and were significant only in 3 dogs.