[Changes in the tetrapolar rheographic indices of adult and old rats under stress]

Experiments with adult (8-10 months) and old (24-26 months) male rats were carried out to investigate the effect of stress on the values of central hemodynamics and inotropic cardiac function--stroke volume, minute volume, stroke index, as well as output volume rate, output volume rate index and systolic frequency. It is found that stress causes more significant disturbance of inotropic function in old rats as compared with adult animals. This disorder occurs earlier in old rats. Probably it is a result of more pronounced damaging effect of the stress on the myocardium of old rats against the background of decreased compensatory systemic abilities.