EFFECTS OF AMRINONE ON CONTRACTION AND ACTION POTEN-TIAL OF ISOLATED PAPILLARY MUSCLES IN GUINEA PIGS / 西安交通大学学报(医学版)

ABSTRACT

The effects of amrinone on the contraction and action potential of isolated guinca pig papillary muscles were studied with intracellular microelectrodes. When the preparations were exposed to 25 ?mol/L amrinone, their pcak developed tension(DT) was inereased by 65.4%, the maximum rate of force development (dT/dt_(max)) was increased by 50.8% the time to peak developed tension (tPT) was shortened by 15.9%. By raising the concentration of amrinone to 250 ?mol/L, DT and dT/dt_(max) were increased by 98.5% and 91.3%, respectively, and tPT was shortened by 24.7%. Concomitantly, amrinone can prolong the durations of action potential (APD50, APD90)and the effective refractory period (ERP) of the ventricular cells.These results suggest that amrinone (made in China) possesses the obvious positive inotropic effect.