Voltage- and use-dependent effect of 7-chlor-benzyltetrahydropalmatine on sodium currents in guinea pig ventricular myocytes

Yan Sheng; Li Xinhua; Yao Weixing; Xia Guojin; Jigang Mingxing

doi:10.1007/BF02888521

Current Medical Science ›› 1998, Vol. 18 ›› Issue (3) : 137 -140. DOI: 10.1007/BF02888521

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Voltage- and use-dependent effect of 7-chlor-benzyltetrahydropalmatine on sodium currents in guinea pig ventricular myocytes

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Abstract

The whole-cell patch-clamp technique was employed to obtain information about the voltage-dependence and kinetics of interaction of 7-chlor-benzyltetrahydropalmatine (7-C1-BTHP) with cardiac sodium channels. 7-C1-BTHP (30 mol/L) significantly decreased the peak sodium current (from 7. 8±1. 8 nA to 5. 3±1. 4 nA,P<0. 01,n = 5), without producing a shift of the current-voltage curve. It shifted the inactivation curves of sodium current to hyperpolarized potentials, and the V_0.5 was shifted from - (82. 5±2. 5) mV to - (95±2. 4) mV (P <0. 05,n = 4). 7-C1-BTHP produced a significant use-dependent effect that was proportional to the duration of the voltage step. In addition, 7-C1-BTHP slowed the recovery of sodium channel from inactivation, which could explain its use-dependent effects on sodium current. The characteristics of 7-C1-BTHP blockage suggest that this agent binds preferentially to inactivated sodium channels.

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7-chlor-benzyltetrahydropalmatine / myocardium sodium channel current / guinea pig / ventricular myocytes

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Yan Sheng, Li Xinhua, Yao Weixing, Xia Guojin, Jigang Mingxing. Voltage- and use-dependent effect of 7-chlor-benzyltetrahydropalmatine on sodium currents in guinea pig ventricular myocytes. Current Medical Science, 1998, 18(3): 137-140 DOI:10.1007/BF02888521

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