THE ROLE OF HSP70 AND IP3-DAG MECHANISM IN THE ADAPTIVE STABILIZATIONOF STRUCTURES AND HEART PROTECTION

This study has shown that the maximal activation of the IP3-DAG regula tory circuit is observed on the 14th day of adaptation to repeated str esses. This activation is characterized by increased activity of phosp holipase C and of the positive inotropic response of isolated heart to an alpha-agonist. Simultaneously, this activation is accompanied by t he accumulation of five heat shock protein 70 (hsp70) isoforms. The IP 3-DAG circuit activation and the hsp70 accumulation are accompanied by a significant increase in the cardiac resistance to post-ischemic rep erfusion, as evidenced by a considerable decrease in the contracture, arrhythmias and the creatine kinase release into the perfusate. Contin uation of the adaptation to repeated stresses for 28 days leads to com plete reversal of the observed shifts. (C) 1996 Academic Press Limited