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CJAP ›› 2018, Vol. 34 ›› Issue (3): 218-222.doi: 10.12047/j.cjap.5581.2018.052

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Effects of extracellular Ba2+ on L-type calcium current in rat ventricular cardiocytes

MENG Hong-xu, YAO Ming-jiang, REN Jun-guo, LIU Jian-xun   

  1. Institute of Basic Medical Sciences of Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing key Laboratory of Pharmacology of Chinese Materia Medica, Beijing 100091, China
  • Received:2017-03-09 Revised:2017-11-29 Online:2018-05-28 Published:2018-09-08
  • Supported by:

Abstract: Objective: To observe the effect of extracellular Ba2+ on the recording L-type calcium channel of rat ventricular cardiocytes.Methods: Whole-cell patch clamp technique was used to record the currents of L-type calcium channels (ICa,L) in a single ventricular cardiocyte isolated from a rat heart by acute enzymatic digestion combined with mechanical method. Ba2+ was used to replace Ca2+ in Tyrode's solution, and Ba2+ (0~0.8 mmol/L) was directly added to Tyrode's solution to observe the change of the peak current within 15 minutes. The data were repeated with 5 cells or more.Results: ①The inactivation rate of ICa,L was slowed down significantly (P<0.01) with Ba2+ instead of Ca2+ gradually in Tyrode's solution. There was no change in the inactivation rate of ICa,L when the Ba2+ (0.2, 0.4 mmol/L) was added in the extracellular solution, but when 0.8 mmol/L Ba2+ was added, the inactivation rate would slow down significantly (P<0.01). ②Ba2+(0.2, 0.4 mmol/L) added in the extracellular solution could decrease the peak current attenuation. Compared with the group in Tyrode's solution, the peak current attenuation rate of the group in Ba2+ (0.2, 0.4 mmol/L) added in the extracellular solution was decreased significantly at the two time points (10 min, 15 min, P<0.01). ③The extracellular Ba2+ (0.4 mmol/L) could move the current-voltage curve down, change the reversal potential, weaken ICa,L inhibition induced by salvianolic acid A and right-shift concentration-response curve.Conclusion: The addition of Ba2+ to extracellular solution can attenuate the peak current decay, change the voltage-dependent characteristics of calcium channels and influence drug dose-effect relationship when whole-cell patch clamp technique is used to record L-type calcium channel of rat ventricular cardiocytes.

Key words: rat, ventricular myocytes, Ba2+, L-type calcium current, whole-cell patch clamp

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