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Journal of Tongji Medical University

, Volume 18, Issue 3, pp 137–140 | Cite as

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
Article
  • 20 Downloads

Summary

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 V0.5 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.

Key words

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

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Copyright information

© Springer 1998

Authors and Affiliations

  • Yan Sheng
    • 1
  • Li Xinhua
    • 1
  • Yao Weixing
    • 1
  • Xia Guojin
    • 1
  • Jigang Mingxing
    • 1
  1. 1.Department of PharmacologyTongji Medical UniversityWuchan

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