粉防己碱松弛离体新西兰白兔阴茎海绵体作用的研究

目的 :探讨粉防己碱 (Tet)对离体新西兰白兔阴茎海绵体的松弛作用。　方法 :采用离体新西兰白兔阴茎海绵体肌条张力记录法 ,观察Tet对氯化钾 (KCl)和去氧肾上腺素 (PE)诱导收缩的阴茎海绵体肌条的松弛作用 ;L 硝基精氨酸 (L NNA)和亚甲蓝处理后 ,Tet对PE诱导收缩的阴茎海绵体肌条松弛的作用。　结果 :10 μmol/L及3 0 μmol/L的Tet使KCl诱导的最大收缩反应分别降低为 ( 73 .0± 3 .8) %和 ( 41.5± 3 .4) % ,降低程度与Tet的浓度呈正比 (P <0 .0 1)。Tet对 10 μmol/LPE诱导的肌条收缩具有浓度依赖性松弛作用 ,1、10、3 0、10 0 μmol/L的Tet对PE诱导的阴茎海绵体肌条收缩的松弛效应分别为 ( 6.0± 1.4) %、( 2 1.3± 2 .2 ) %、( 47.4± 3 .3 ) %和 ( 68.1±3 .6) % (P <0 .0 1) ;而L NNA及亚甲蓝对Tet的松弛作用没有影响 (P >0 .0 5 )。　结论 :Tet能浓度依耐性地松弛离体新西兰白兔阴茎海绵体 ,其作用机制可能是通过阻滞钙通道 ,而与一氧化氮 环鸟苷酸 (NO cGMP)通路无关

The Relaxation Effects of Tetrandrine on the Corpus Cavernosum Tissue of Rabbit in Vitro

OBJECTIVES: To study the relaxation effects of tetrandrine on the corpus cavernosum tissue of rabbit in vitro. METHODS: 1. The fluctuation of the dose-response relaxation curves for the contraction of KCl induced by tetrandrine was observed with isolated rabbit corpus cavernosum tissue. 2. Isolated strips of rabbit corpus cavernosum tissue were precontracted with 10 mumol/L phenylephrine(PE). Relaxation in response to cumulative doses of tetrandrine was determined in the absence and presence of nitric oxide synthase inhibitor (L-NNA) and soluble guanylate cyclase inhibitor (methylthioninium). RESULTS: 1. The dose-response curves of KCl were shifted to the right nonparallelly, and the maximal responses were depressed to (73.0 +/- 3.8)% and (41.5 +/- 3.4)%, respectively, in the presence of tetrandrine(10 mumol/L, 30 mumol/L). 2. On rabbit cavernosal muscle stripes precontracted with PE(10 mumol/L), increasing concentrations of tetrandrine (1 mumol/L, 10 mumol/L, 30 mumol/L and 100 mumol/L) showed dose dependent relaxation [(6.0 +/- 1.4)%, (21.3 +/- 2.2)%, (47.4 +/- 3.3)%, and (68.1 +/- 3.6)%, P < 0.01]. However, in the meantime, it was found that these relaxation effects were not affected by the presence of L-NNA and methylthioninium (P > 0.05). CONCLUSIONS: Tetrandrine was effective in relaxing rabbit corpus cavernosum tissue in vitro in a dose-dependent style. The mechanism might be related with its blocking effect on calcium channel, but not the NO-cGMP passage.