乙醇对离体家兔阴茎海绵体的松弛效应及其作用机制

目的:观察乙醇对离体家兔阴茎海绵体的效应并探讨其可能机制。方法:台式生理记录仪测定海绵体张力,放射免疫测定法测定阴茎海绵体cAMP和cGMP含量。结果:①1.25%(V/V)的乙醇能明显增强异丙肾上腺素(10-9～10-5mol/L)对海绵体肌条的舒张效应。②100、300μmol/L的腺苷酸环化酶抑制剂SQ22536能使乙醇(0.25%～3.5%,V/V)对去氧肾上腺素诱导收缩的肌条的舒张曲线右移,100、300μmol/LSQ22536分别使最大舒张效应由(105.12±3.39)%降低到(97.00±2.57)%和(91.09±2.42)%,EC50由(1.18±0.09)%分别增加到(1.36±0.10)%和(1.68±0.13)%(P均<0.05)。③乙醇可浓度依赖性增加家兔阴茎海绵体cAMP含量,而对cGMP含量无影响。④对于提取的兔离体海绵体组织细胞膜碎片上的腺苷酸环化酶,乙醇可浓度依赖性地增强其活性。结论:乙醇可舒张离体家兔海绵体平滑肌,其作用可能是通过cAMP信号转导通路实现的。

Relaxant Effect of Ethanol on Isolated Rabbit Corpus Cavernosum and Its Mechanism

OBJECTIVE: To study the relaxant effect of ethanol on the isolated rabbit corpus cavernosum and its possible mechanism. METHODS: The tension of isolated smooth muscle strips was recorded by the plateform physiological grapher, and the concentrations of cAMP and cGMP in the rabbit corpus cavernosum were measured by 125I radioimmunoassay. RESULTS: The 1.25% (V/V) ethanol significantly augmented the corporal relaxation induced by isoprenaline (10(-9) - 10(-5) mol/L). Ethanol-induced relaxation was inhibited by 100 micromol/L and 300 micromol/L SQ22536 (an adenylate cyclase inhibitor). Emax was depressed from (105.12 +/- 3.39) % to (97.00 +/- 2.57) % in the presence of 100 micromol/L SQ22536 or (91.09 +/- 2.42) % in the presence of 300 micromol/L SQ22536. EC50 was increased from (1.18 +/- 0.09)% (V/V) to (1.36 +/- 0.10) % in the presence of 100 micromol/L SQ22536 (P < 0.05) or (1.68 +/- 0.13) % (in the presence of 300 micromol/L SQ22536) (P < 0.05) respectively. Ethanol significantly elevated the level of cAMP but not that of cGMP in the isolated rabbit corpus cavernosum, and it also significantly enhanced the activity of the adenylate cyclase (AC) extracted from the rabbit corpus cavernosum in a dose-dependent manner. CONCLUSION: Ethanol has a relaxant effect on the isolated rabbit corpus cavernosum, which may be associated with the cAMP signaling pathway.