Electrophysiological properties of rat heart cells in vitro and in tissue culture.

Some electrical properties of right ventricles of neonatal rats and of aggregates from collagenase-dissociated cells from the same tissue are compared. The duration of the action potential does not change upon changing the stimulation frequency both in ventricles and aggregates; a decrease in temperature increases duration in both preparations to the same extent. The take-off potential and the maximal rate of rise of the action potential decrease in the same way in both preparations, while the time course of these changes is also comparable. It is concluded that the dissociation and aggregation procedure does not interfere with the membrane properties upon which the measured parameters are based; thus, aggregates are well suited for a realistic voltage-clamp analysis.