Abstract
The cerebral ischemic response (CIR) was elicited in rabbits after permanent occlusion of the vertebral arteries by temporarily occluding the common carotid arteries or the internal and external carotid arteries. It was found that infusion of saline into the common carotid artery during the CIR resulted in a delay of the onset of apnea and an attenuation of the blood pressure increase, suggesting that mechanical factors play a role in the initiation of the CIR. Occlusion of either the internal or external carotid artery alone failed to elicit changes in blood pressure or respiration. The CIR could only be elicited during periods when the internal and external carotid arteres were jointly occluded, suggesting that the ischemic stimulus may act upon peripheral sites as well as upon central sites. Finally, the bradycardia component could be eliminated by ventilation and sinoaortic denervation, suggesting that the bradycardia component is a secondary response to cerebral ischemia.