Afferent pathways of reflex hypotension and bradycardia during coronary occlusion.
Neural afferent pathways mediating reflex hypotension and bradycardia during coronary occlusion (CO) were determined mainly on the right side in anesthetized cats. Brief occlusion of the left anterior descending (LAD) or circumflex coronary artery (Cx) reuslted in significant hypotension and bradycardia, both of which could be attenuated by bilateral (BVB), unilateral right (RVB), or left vagal cold blockade (LVB) in the nec. The degree of attenuation in the responses was greater as follows: BVB greater than RVB greater than LVB for LAD occlusion, and BVB greater than RBV = LBV for Cx occlusion. Randomized section of cardiac nerves, i.e., the pericoronary nerve, vagal cardiac nerve trunk, and caudal vagal cardiac nerves on the right side produced significant attenuations in the circulatory responses to CO. These results indicate that vagal afferent activity transmitted via these cardiac nerves plays an important role in mediating the reflex responses to CO. This conclusion was further substantiated by electrical stimulation of afferent fibers in thee nerves or by recording increased afferent spontaneous activity form them during CO.
D000344:Afferent Pathways / Q000033:anatomy & histology / Q000502:physiology; D000818:Animals; D001794:Blood Pressure; D002415:Cats; D003331:Coronary Vessels / Q000502:physiology*; D004558:Electric Stimulation; D004562:Electrocardiography; D006321:Heart / Q000294:innervation; D006339:Heart Rate; D007511:Ischemia; D012018:Reflex / Q000502:physiology*; D014630:Vagus Nerve / Q000033:anatomy & histology / Q000502:physiology*