Effects of Tetrahydroberberine and l─tetrahydropalmatine on^(45)Ca Influx in the Smooth Muscles of Rabbit Thoracic Aorta and Renal Artery

Thispaperreportstheeffectsoftetrahydroberberine(THB)andl-te-trahydropalmatine(THP)onhighK+-provoked45Cainfluxinrabbitthoracicaorta(TA)andrenalartery(RA).Likeverapamil(Ver),bothTHBandTHP(1,10μmol/L)significantlyinhibitedhighK+-provoked45Cainflux(P<0.01)withoutaf-fectingbasic45CainfluxinTAandRA.Thepotencyorderofthemwasasfolows:Ver>THB>THP.NoapparentlyselectiveresponseinTAandRAwasfoundtoeachdrug.TheseresultsindicatethatTHBandTHPmayhaveblockingeffectonCa2+en-trythroughpotential-dependentchannels.