Rho/rho-kinase signalling in chronically alcohol-fed mice

Background/aim: The effects of chronic ethanol consumption on male sexual function are debateable, and its effects on the Rho/Rho-kinase pathway are unknown. Therefore, we investigated smooth muscle reactivity and Rho/Rho-kinase signalling in the corpus cavernosum of ethanol-fed mice. Materials and methods: Ethanol was added to drinking water at 5% concentration in the first 2 days with 5% increment every subsequent 2 days, up to a final concentration of 20% for 45 days. Corpora cavernosa were isolated and a cumulative dose-response curve to phenylephrine was obtained. Acetylcholine (10-6 M), electrical field stimulation (EFS, 40 V, 8-16 Hz) and Y-27632 (10(-6)-10(-5) M)-induced relaxations were compared in the control and ethanol groups. Results: Blood ethanol levels in the control and ethanol-treated mice were 1.5 +/- 0.3 mg/dL and 37.4 +/- 4.1 mg/dL (P < 0.001), respectively. Phenylephrine-induced contractile responses were potentiated in the ethanol group, with pD 2 values of 4.92 +/- 0.18 and 5.71 +/- 0.21 (P < 0.01) in the corpus cavernosum obtained from control and alcohol-fed mice, respectively. The relaxant responses to acetylcholine and EFS, but not Y-27632, were significantly augmented in the corpus cavernosum obtained from ethanol-treated mice. However, expression and activation of Rho-kinase remained unchanged in the alcohol group. Conclusion: Ethanol drinking may increase sensitivity to both vasoconstrictors and vasodilators in the mouse corpus cavernosum without any alteration in Rho/ Rho-kinase signalling.