(-)-Epigallocatechin gallate inhibits the pacemaker activity of interstitial cells of cajal of mouse small intestine

Abstract

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°C and Ca2+ 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 Ca2+ -activated K+ channel blocker. Also, we found that EGCG inhibited the spontaneous [Ca2+] oscillations in cultured ICC. In conclusion, EGCG inhibited the pacemaker activity of ICC and reduced [Ca2+]i oscillations by cAMP-, cGMP-, ATP-sensitive K+ channel-independent manner.