Effects of Ginkgolide B on action potential and calcium, potassium current in guinea pig ventricular myocytes |
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Authors: | Qi Xiao-yan Zhang Zhi-xiong Xu You-qiu |
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Affiliation: | Department of Physiology, Shanghai University of Traditional Chinese medicine, Shanghai 200032, China. |
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Abstract: | AIM: To investigate the effect of Ginkgolide B (GB) on action potential (AP), delayed rectifier potassium current (IK), and L-type calcium current (I(Ca-L)) in guinea pig ventricular myocytes. METHODS: Single ventricular myocytes were isolated by an enzymatic dissociation method. AP, IK, I(Ca-L) were recorded by whole-cell patch-clamp technique in either current or voltage clamp mode. RESULTS: GB shortened APD in a concentration-dependent manner. GB 0.1, 1, and 10 micromol/L shortened APD50 by 7.9% (n=5, P>0.05), 18.4% (n=5, P<0.01), and 28.9% (n=6, P<0.01), respectively; APD90 by 12.4% (n=5, P>0.05), 17.6% (n=5, P<0.01), 26.4% (n=5, P<0.01), respectively. GB increased IK in a concentration-dependent manner. GB 0.1, 1, and 10 micromol/L increased IK by 20.1% (n=6, P<0.05), 43.1% (n=6, P<0.01), 55.6% (n=6, P<0.05); increased IK tail by 10.7% (n=6, P<0.05), 25.1% (n=6, P<0.05), and 37.7% (n=6, P<0.05), respectively at testing potential of +50 mV and shift the I-V curve of IK upward. But GB had no significant effect on I(Ca-L) at above concentrations. CONCLUSION: GB significantly shortened APD in a concentration-dependent manner which mainly due to increase of IK. |
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Keywords: | Ginkgo biloba patch-clamp techniques myocardium action potentials potassium channels cal- cium channels |
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