粉防己碱(Tet)对兔子阴茎海绵体平滑肌细胞质中自由钙离子浓度的影响(英文)

目的:探讨粉防己碱(tetrandrine,Tet)松弛阴茎海绵体平滑肌的作用机制。方法:体外培养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(1,10,100μmol/L)对平滑肌细胞内静息Ca~(2 )]_i无明显影响(P>0.05)。当细胞外钙离子浓度为2.5 mmol/L 时,Tet(1μmol/L,10 μmol/L,100 μmol/L)抑制了高钾和去氧肾上腺素(PE)导致的细胞内Ca~(2 )]_i 升高(P<0.05),这种抑制作用具有浓度依赖性。在无细胞外钙时,1 μmol/L和10μmol/L Tet 对 PE 引起的细胞内Ca~(2 )]_i 升高无明显影响(P>0.05);而100 μmol/L Tet 能明显抑制 PE 引起的细胞内Ca~(2 )]_i 升高(P<0.05)。结论:Tet 通过阻滞电压依赖性钙通道、α_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。

Effects of tetrandrine on cytosolic free calcium concentration in corpus cavernosum smooth muscle cells of rabbits

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 micromol/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 micromol/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 micromol/L) had no inhibitory effects on Ca(2+)](i) elevation induced by PE (P>0.05). However, Tet (100 micromol/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 alpha(2)-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.