Effect of rhyncophylline on potassium channels in isolated rat or guinea pig ventricular myocytes
Wang, X.L.; Zhang, L.M.; Hua, Z.
Yao Xue Xue Bao 29(1): 9-14
1994
ISSN/ISBN: 0513-4870 PMID: 8036902 Document Number: 429248
Effects of rhynchophylline (Rhy) on the voltage-dependent potassium channels in isolated rat and guinea pig ventricular myocytes were studied by using patch clamp whole cell recording techniques. Rhy was found to reduce the steady-state outward current in rat ventricular myocytes when cells were depolarized from holding potential -40 mV to 0 mV. After blocking Ca-2+ inward current with CdCl-2 0.1 mmol/L, a K+ transient outward current (I-A) can be recorded. Rhy 30 mu-mol/L inhibited the I-A 30% when depolarized to +50 mV from the holding potential. The delayed outward (I-K) and outward tail current (I-tail) were also reduced 30% and 60%, respectively by Rhy 30 mu-mol/L which responded to 4.5 sec long pulse from -40 mV to -50 mV. Whereas, the inward rectifying current (I-K1) was not changed by Rhy. The present study suggests that the antiarrhythmic action of Rhy was partially due to the K+ channel blocking effects.