Effect of Naloxone on Cortical Blood Flow During Focal Cerebral Ischemia in Cats

Park, S K; Kim, S H; Chang, J W; Lee, K C

Abstract

The effect of naloxone on anesthetized cats with focal cerebral ischemia induced by middle cerebral artery(MCA) clipping through the transorbital approach was studied. Regional cerebral cortical blood flow was measured in the bilateral MCA territories at specified intervals by the hydrogen clearance method. The cats which received physiologic saline served as controls. Ten other cats all received naloxone administered intravenously. They were divided into two groups of five cats each, the cats of one group having received a 2mg/kg injection 20 minutes postocclusion followed by 2mg/kg/hour x 4 hours by continuous intravenous infusion, and the cats of the other group having received a 10mg/kg injection 20 minutes postocclusion followed by 10mg/kg/hour x 4 hours by continuous intravenous infusion. It was observed that in the cats of the group receiving the greater amount of naloxone, the rate of cerebral cortical blood flow increased to a level significantly higher than the rate of flow in the controls ; the increase in the rate of flow in the cats of the group receiving the smaller amount of naloxone did not constitute a rise in the rate to a level significantly higher than that of the rate of flow in the controls.