[The biphasic nature of the phenomenon of structural adaptational stabilization during the long-term adaptation of the body to stress].

During long-term (28 days) adaptation of the body to stress, the structural adaptational stabilization phenomenon (SASP) has a marked two-phase pattern: (1) SASP formation during nearly 14 days when protein transcription in heat shock was activated, hsp 70 was substantially accumulated and cardiac resistance to reperfusion damage drastically increased and (2) SASP reduction occurring despite continuous adaptation. By day 28 myocardial adaptation showed only two hsp 70 isoforms of the five revealed on day 14 of stress adaptation. Correspondingly, by day 28, the anticontractural effect of adaptation and its capacity of retaining the high contraction amplitude turned out to vanish in reperfusion. Moreover, ventricular fibrillation and ventricular tachycardia were observed in the control animal hearts during reperfusion, whereas these arrhythmias were seen only in 25 and 50% cases on days 14 and 28, respectively.