[Age related electrophysiological modifications in rat myocardium]

During aging the electrical and mechanical phenomena of the heart are impaired. We studied the effect of aging using standard microelectrode technique on action potentials obtained in papillary muscle from 1, 3, 6 and 18 month old rats. The action potential of myocardial cells is significantly prolonged and changes resemble those observed during cardiac overload. The possible cause of the slower action potentials is the alteration of Ca2+ transients due to a reduced rate of Ca2+ sequestration by the sarcoplasmic reticulum associated with a possible alteration of K+ currents. These developmental changes are considered as an expression of adaptation of the heart with aging.