Reduction of hyperthermic ischemic acidosis by a conditioning event in cats

Abstract

We investigated the effects of multiple episodes of cerebral ischemia on intracellular brain pH using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy. Four cats were subjected to two 16-minute episodes of complete global cerebral ischemia 6 hours apart;the second episode occurred under hyperthermic conditions (mean±SD body temperature 40.8±0.4° C). Intracellular pH in these four cats was compared with that in nine cats subjected to a single 16-minute episode of complete global cerebral ischemia under hyperthermic conditions (mean±SD body temperature 40.6±0.2° C). Intracellular pH during hyperthermic recirculation was significantly (p<0.03) greater in cats subjected to a previous ischemic event than that in cats subjected to only a single hyperthermic ischemic event. We speculate that the induction of heat shock proteins by an initial ischemic event may protect brain tissue from further ischemic insult. © 1989 American Heart Association, Inc.