摘要
Aim:To study the relaxation mechanisms of tetrandrine(Tet)on the corpus cavernosum smooth muscle.Methods: The corpus cavernosum smooth muscle cells from New Zealand white rabbits were cultured in vitro.[Ca^(2+)]_i was measured by Fluorescence Ion Digital Imaging System,using Fluo-2/AM as a Ca^(2+)-sensitive fluorescent indicator. Results:Tet(1,10 and 100 μmol/L)had no effect on the resting [Ca^(2+)]_i(P>0.05).In the presence of extracellular Ca^(2+)(2.5 mmol/L),Tet(1,10 and 100 μmol/L)inhibited [Ca^(2+)]_i elevation induced by high K^+ and phenylephrine(PE) in a concentration-dependent manner(P<0.05).In calcium free solution containing egtaic acid,Tet(1 and 10 μmol/L) had no inhibitory effects on [Ca^(2+)]_i elevation induced by PE(P>0.05).However,Tet(100μmol/L)inhibited [Ca^(2+)]_i elevation induced by PE(P<0.05).Conclusion:Tet inhibited the Ca^(2+)influx from the extracellular site via voltage- activated Ca^(2+)channel and α_1-adrenoceptor-operated Ca^(2+)channel.At a high concentration,Tet might inhibit the cytosolic calcium pool release in cultured corpus cavernosum smooth muscle cells.This inhibitory action on [Ca^(2+)]_i might be one of the relaxation mechanisms of Tet on the corpus cavernosum smooth muscle.(Asian J Androl 2006 Jul;8:405-409)
Aim:To study the relaxation mechanisms of tetrandrine(Tet)on the corpus cavernosum smooth muscle.Methods: The corpus cavernosum smooth muscle cells from New Zealand white rabbits were cultured in vitro.[Ca^(2+)]_i was measured by Fluorescence Ion Digital Imaging System,using Fluo-2/AM as a Ca^(2+)-sensitive fluorescent indicator. Results:Tet(1,10 and 100 μmol/L)had no effect on the resting [Ca^(2+)]_i(P>0.05).In the presence of extracellular Ca^(2+)(2.5 mmol/L),Tet(1,10 and 100 μmol/L)inhibited [Ca^(2+)]_i elevation induced by high K^+ and phenylephrine(PE) in a concentration-dependent manner(P<0.05).In calcium free solution containing egtaic acid,Tet(1 and 10 μmol/L) had no inhibitory effects on [Ca^(2+)]_i elevation induced by PE(P>0.05).However,Tet(100μmol/L)inhibited [Ca^(2+)]_i elevation induced by PE(P<0.05).Conclusion:Tet inhibited the Ca^(2+)influx from the extracellular site via voltage- activated Ca^(2+)channel and α_1-adrenoceptor-operated Ca^(2+)channel.At a high concentration,Tet might inhibit the cytosolic calcium pool release in cultured corpus cavernosum smooth muscle cells.This inhibitory action on [Ca^(2+)]_i might be one of the relaxation mechanisms of Tet on the corpus cavernosum smooth muscle.(Asian J Androl 2006 Jul;8:405-409)
