粉防己碱对新西兰白兔阴茎海绵体平滑肌细胞内游离钙离子浓度的影响

Effects of tetrandrine on cytosolic free calcium concentration incorpus cavernsum smooth muscle cells of rabbits

目的探讨粉防己碱（Tet）松弛阴茎海绵体平滑肌的作用机制。方法体外培养的第3，4代新西兰白兔阴茎海绵体平滑肌细胞，经钙荧光指示剂Fluo-2／AM负载后，用荧光离子数字成像系统观察Tet对平滑肌细胞内[Ca^2＋]i的影响。结果Tet对平滑肌细胞内静息[Ca^2＋]i无明显影响（P〉0.05）。在细胞外钙浓度为2．5mmol／L时，1、10和100μmol／L Tet对高钾和去氧肾上腺素（PE）引起的细胞内[Ca^2＋]i升高有浓度依赖性地抑制作用。对40mmol／LKCl引起的细胞内[Ca^2＋]i升高的抑制率分别为22．0％、41．0％和73．0％（P〈0．05）。对10μmol／LPE引起的细胞内[Ca^2＋]i升高的抑制率分别为15．0％、26．4％和46．6％（P〈0．05）。在无细胞外钙时，1μmol／L和10μmol／LTet对PE引起的细胞内[Ca^2＋]i升高，无明显影响（P〉0．05）；而100μmol／LTet能明显抑制PE引起的细胞内[Ca^2＋]i升高，抑制率为28．2％（P〈0．05）。结论Tet可能通过阻滞电压依赖性钙通道、俚1受体依赖性钙通道和抑制细胞内钙库释放，降低阴茎海绵体平滑肌细胞内[Ca^2＋]i水平，这是Tet松弛阴茎海绵体平滑肌的作用机制之一。

Objective To study the relaxation mechanisms of tetrandrine （Tet） on. Methods In the in vitro cultured corpus cavernsum smooth muscles of 3rd to 4th in New Zealand rabbits, [ Ca^2＋ ] i was measured by fluorescence ion digital Imaging system （FIDIS）, using Fluo-2/AM as a Ca^2＋ -sensitive fluorescenct 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 extraceilular Ca^2＋ （2.5 mmol/L） ,Tet （ 1,10 and 100 μmol/L） had inhibitory effects on [ Ca^2＋ ]i elevation induced by high K ~ and Phenylephrine （PE） in a concentration-dependent manner （P 〈0.05）. In the absence of extraceilular Ca^2＋ containing egtaic acid （EGTA）, Tet （1 and 10 μmol/L） had no inhibitory effects on [ Ca^2＋ ] i elevation induced by PE （ P 〉 0.05 ）. However, Tet （ 100 txmol/L） inhibited [ Ca^2＋ ] i elevation induced by PE （P 〈 0.05）. Conclusion Tet inhibited the Ca^2＋ influx from the extraeellular site via vohage-actived Ca^2＋ channel and α1-receptor-operated Ca^2＋ channel. At a high concentration, Tet may inhibit the cytosolic calcium pool release in cultured corpus cavemsum smooth muscle cells. This might be one of the relaxation mechanisms of Tet on the corpus cavemsum smooth muscles.