[Electrophysiological effects of guan-fu base A on action potentials of guinea pig ventricular papillary muscles].
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.
Zhou
L M
LM
Department of Medicine, Shanghai Ninth People's Hospital, Shanghai Second Medical University, China.
Xu
J M
JM
Chen
X H
XH
Xie
Y S
YS
D000200:Action Potentials / Q000187:drug effects; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D006168:Guinea Pigs; D006576:Heterocyclic Compounds, 4 or More Rings; D066298:In Vitro Techniques; D010210:Papillary Muscles / Q000187:drug effects* / Q000502:physiology; D012032:Refractory Period, Electrophysiological / Q000187:drug effects
D000470:Alkaloids; D000889:Anti-Arrhythmia Agents; D006576:Heterocyclic Compounds, 4 or More Rings; C040615:Guan-fu base A