Department of Rehabilitation, College of Medicine, Chosun University, Gwangju 501-759, Korea.
Korean J Physiol Pharmacol. 2008 Jun;12(3):111-5. doi: 10.4196/kjpp.2008.12.3.111. Epub 2008 Jun 30.
The effects of (-)-epigallocatechin gallate (EGCG) on pacemaker activities of cultured interstitial cells of Cajal (ICC) from murine small intestine were investigated using whole-cell patch-clamp technique at 30 and Ca(2+) image analysis. ICC generated spontaneous pacemaker currents at a holding potential of -70 mV. The treatment of ICC with EGCG resulted in a dose-dependent decrease in the frequency and amplitude of pacemaker currents. SQ-22536, an adenylate cyclase inhibitor, and ODQ, a guanylate cyclase inhibitor, did not inhibit the effects of EGCG. EGCG-induced effects on pacemaker currents were not inhibited by glibenclamide, an ATP-sensitive K(+) channel blocker and TEA, a Ca(2+)-activated K(+) channel blocker. Also, we found that EGCG inhibited the spontaneous Ca(2+) oscillations in cultured ICC. In conclusion, EGCG inhibited the pacemaker activity of ICC and reduced Ca(2+) oscillations by cAMP-, cGMP-, ATP-sensitive K+ channel-independent manner.
采用全细胞膜片钳技术结合钙离子成像技术，研究了（-）-表没食子儿茶素没食子酸酯（EGCG）对培养的小鼠小肠间质细胞（ICC）起搏活动的影响。在 -70 mV 的保持电位下，ICC 产生自发性起搏电流。EGCG 处理 ICC 可使起搏电流的频率和幅度呈剂量依赖性降低。腺苷酸环化酶抑制剂 SQ-22536 和鸟苷酸环化酶抑制剂 ODQ 不能抑制 EGCG 的作用。ATP 敏感性钾通道阻断剂格列本脲和 Ca2+-激活钾通道阻断剂 TEA 均不能抑制 EGCG 诱导的起搏电流。此外，我们发现 EGCG 抑制了培养的 ICC 中的自发性[Ca2+]（i）振荡。总之，EGCG 通过 cAMP-、cGMP-、ATP 敏感性钾通道非依赖性方式抑制 ICC 的起搏活性并减少[Ca2+]（i）振荡。
