Electrophysiological effects of guan-fu base a on action potentials of guinea pig ventricular papillary muscles
Zhou, L.M.; Xu, J.M.; Chen, X.H.; Xie, Y.S.
Zhongguo Yao Li Xue Bao 12(5): 465-467
1991
ISSN/ISBN: 0253-9756 PMID: 1819905 Document Number: 380180
Guan-fu base A (GA), an alkaloid first isolated in China, 50 mg.L-1 decreased the action potential amplitude and the maximal rate of depolarization (Vmax) of guinea pig papillary muscles in vitro. GA shortened the action potential period at 90% repolarization (APD90) without significant effect on the effective refractory period (ERP), resulting in an increased ERP/APD90 ratio. GA 50 mg.L-1 also slowed the conduction speed. The inhibiting effect of GA on Vmax showed frequency- and potential-dependent manners.