Cerebral ischemia produced by four-vessel occlusion in the rat: A quantitative evaluation of cerebral blood flow

Abstract

Cerebral ischemia was produced in the rat by simultaneous occlusion of the vertebral and carotid arteries according to the method of Pulsinelli and Brierly (Stroke 10: 267, 1979). Local cerebral blood flow (CBF) was determined by polarographic and autoradiographic techniques. Hydrogen-clearance measurement showed that mean CBF fell in four monitored regions of the hemispheres to between 0.11 and 0.18 ml/g/min, being least in deep rostral gray, intermediate in superficial gray, and greatest in deep caudal gray. However, individual animals had local CBF in excess of 0.20 and even 0.30 ml/g/min, and no animal showed zero CBF. When animals were rendered hypotensive (MABP of 50 Torr) during vascular occlusion, mean CBF ranged between 0.03 and 0.10 ml/g/min in the same regional order. With hypotension, total arrest of flow occurred. Autoradiographic data confirmed the above findings and indicated adequate CBF to the lower brainstem. During vascular occlusion, sufficient CBF may be present to sustain cerebral tissue as in animals with a well developed spinal circulation or an inadvertently patent vertebral artery.