Effects of ginseng total saponins on pacemaker currents of interstitial cells of Cajal from the small intestine of mice

Although ginsenosides have a variety of physiologic or pharmacologic functions in various regions, there are only a few reports on the effects of ginsenosides on gastrointestinal (GI) motility. We studied the modulation of pacemaker activities by ginseng total saponins in the interstitial cells of Cajal (ICC) using the whole cell patch-clamp technique. Externally applied ginseng total saponins (GTS) produced membrane depolarization in the current-clamp mode and increased tonic inward pacemaker currents in the voltage-clamp mode. The application of flufenamic acid or niflumic acid abolished the generation of pacemaker currents, but only treatment with flufenamic acid inhibited the GTS-induced tonic inward currents. The tonic inward currents induced by GTS were not inhibited by the intracellular application of guanosine 5'-[beta-thio]diphosphate trilithium salt. Pretreatment with a Ca2(+)-free solution, with U-73122, an active phospholipase C inhibitor, and with thapsigargin, a Ca-2'- ATPase inhibitor of the endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the GTS-induced action. However, treatment with chelerythrine and calphostin C, protein kinase C inhibitors, did not block the GTS-induced effects on the pacemaker currents. These results suggest that ginsenosides modulate the pacemaker activities of the ICC, and the ICC can be targets for ginsenosides, and their interaction can affect intestinal motility.