EXPERIMENTAL CONSIDERATION OF VERTEBRAL ARTERY-CAROTID ARTERY ANASTOMOSES

Abstract

With reservations and precautions, preliminary information may be gained concerning the intracranial action of a chemical or drug by injections into the vertebral artery without carotid denervation. However, even inadvertent partial occlusion of the common carotid, or other obstruction to its normal flow, throws into play a free vertebral-carotid anastomotic circulation by virtue of which the chemically sensitive carotid body reflex region is in many cases as freely reached by the chemical as though it were injected directly into the normally patent common carotid. Mere occlusion of the common carotids does not eliminate and in many cases probably does not even diminish the role that the carotid reflex zone may play in the response to a chemical injected into the general circulation. If cyanide or sulfide has a central augmentative influence on carotid sinus respiratory impulses, it is of such magnitude as to require a series of statistically treated quantitative expts. for its study.