The feasibility exploration of cultured newborn rat ventricular myocyte taking the place of acutely enzymatic isolated myocardium for study in electrophysiology of pacemaker current

Objective To investigate the feasibility of cultured rat ventricular myocytes taking the place of acutely enzymatic isolated myocardia for study in the pacemaker current electrophysiology. Methods By using patch-clamp technique, the whole-cell pacemaker currents were recorded to study the difference of pacemaker current electrophysiology between neonatal rat ventricular myocytes isolated acutely and maintained in cell culture. Results The cell membrane capacitances (Cm) were significantly decreased in myocardia even upon short term of cell culture. The Cm of myocardia cultured 1-3 day were (43±3) pF,with decreased 23% compared to acute enzymatic isolated cells (56±7) pF, P0.01. It seemed like the Cm increased slightly upon cell cultured time, but no significant difference appearing among various culture stages (P0.05) .No significant difference of pacemaker current electrophysiological character, such as reverse potential, current density, active threshold and V0.5, was detected from different cell group (P0.05). Conclusion The cultured myocardium can take place of acute enzymatic isolated myocardium used to study in pacemaker current. The cells cultured no more than one week may be more suitable to this kind of electrophysiological experiment.