[Effects of panaxadiol saponins isolated from Panax notoginseng on intracellular and extracellular calcium].

Panaxadiol saponins (PDS) contain saponins Panax notoginseng B1 and E. The spontaneous beating induced by isoproterenol in isolated rat right atria and the increase of contractile force induced by Ca2+ in isolated guinea pig colon were inhibited by PDS 75 and 150 micrograms.ml-1, respectively and perhexiline 6.25 and 12.5 mumol.L-1, respectively. It suggested that PDS could block the potential-dependent and receptor-operated calcium channel in smooth muscle. PDS 150 micrograms.ml-1 and perhexiline 6.25 mumol.L-1 depressed the contractile force induced by norepinephrine and Ca2+ in isolated rat aortic strips in Ca(2+)-free Krebs' solution. It suggested that PDS and perhexiline not only inhibited the release of intracellular Ca2+ but also blocked the inflow of extracellular Ca2+.