ALTERATIONS OF CYCLIC NUCLEOTIDE‐RELATED ENZYMES AND ATPase DURING UNILATERAL ISCHEMIA AND RECIRCULATION IN GERBIL CEREBRAL CORTEX

Abstract

Abstract— Several enzyme activities were determined in gerbil cerebral cortex during unilateral ischemia or in the post‐ischemic period following 1 h of ischemia. Adenylate cyclase and Na + ‐K + ‐activated ATPase showed essentially the same pattern. Neither enzyme changed during ischemia but the activities decreased on recirculation to 40–60% of right side control by 5 h. The ATPase had returned to control level by 20h; the adenylate cyclase by 7 days of recirculation. Particulate cyclic AMP‐dependent protein kinase in the ischemic left hemisphere decreased throughout the 6h of ischemia. It remained depressed in the first 5 h of the post‐ischemic period but returned to control by 20 h. The soluble protein kinase activity, the soluble cyclic AMP and cyclic GMP phosphodiesterase and the Mg 2+ dependent ATPase did not change significantly during the ischemic or post‐ischemic periods. The results suggest that ischemia and/or recirculation may affect cellular membranes and membrane‐bound enzymes, in particular. Furthermore, the results imply that despite apparent metabolite recovery during the post‐ischemic period, enzymatic changes are occurring that may be important for both the quality of recovery and the response to further ischemic insult.