Carotid Sinus Reflex Control of Coronary Blood Flow

1968 Circulation Research  
The role of the carotid sinus reflex in control of the blood flow in the left circumflex coronary artery was studied in nine open-chest dogs anesthetized with chloralose. Flow was measured with an electromagnetic flowmeter. The effects of bilateral common carotid occlusion were examined in a three-part experiment in each dog. (1) Under vagotomy (control) conditions, occlusion of both common carotid arteries resulted in tachycardia, increased blood pressure, and a decrease in coronary artery
more » ... stance. (2) After beta-receptor blockade with propranolol, 1.0 ing/kg, carotid sinus hypotension still resulted in increased blood pressure but the tachycardia was blocked, and coronary artery resistance increased. (3) Following rapid cardiac sympathectomy, carotid sinus hypotension still resulted in a reflex rise in systemic blood pressure but coronary resistance remained steady. This demonstrated the reflex nature of the increased coronary resistance observed after beta-receptor blockade. It is concluded that the coronary circulation is under reflex control and that sympathetic coronary artery vasomotion is a part of a carotid sinus reflex. Recent experiments indicate that the coronary circulation has sympathetic neural Downloaded from Laboratories), 1.0 mg/kg, was given intravenously. After heart rate, blood pressure, and coronary flow became steady (5 to 10 minutes), three more carotid sinus reflexes were elicited by common carotid occlusions.
doi:10.1161/01.res.23.2.223 pmid:5662575 fatcat:jicxm656zzfq3nqffezfblabnu