OBJECTIVETo study the effect of Ginkgo biloba extract 50 (GBE50), a new multicomponent drug with a polyvalent action extracted from the leave of Ginkgo biloba, on the action potentials in normal and simulated ischemic guinea pig papillary muscles.

METHODStandard intracellular microelectrode technique was used to examine the effects of GBE50 on the action potential parameters [action potential amplitude (APA), overshoot, rest potential, action potential amplitude at 20%, 50%, 90% of repolarization (APD20, APD50, APD90)].

RESULTIn normal guinea pig cardiac papillary muscles, GBE50 (20, 50, 100 mg x L(-1)) shortened APD50 and APD90, and did not affect the rest potential parameters. In simulated ischemic guinea pig cardiac papillary cells, action potential duration was significantly shortened, resting potential and action potential amplitude were reduced. 100 mg x L(-1) GBE50 partly attenuated the change induced by ischemia.

CONCLUSIONGBE50 shortened APD of normal guinea pig cardiac papillary cells in a concentration-dependent manner. Under ischemia, all action potential parameters were reduced . GBES0 could alleviate the electrophysiological heterogeneity of ischemic myocardium, which may attenuate myocardial ischemia and block the onset of arrhythmia.