Original articleThe role of arachidonic acid/cyclooxygenase cascade, phosphodiesterase IV and Rho-kinase in H2S-induced relaxation in the mouse corpus cavernosum

BackgroundPenile corpus cavernosum is an extremely vascularized tissue and cavernosal smooth muscle tone is regulated by the balance between contractile and relaxant factor. We investigated the possible role of arachidonic acid/cyclooxygenase cascade, phosphodiesterase IV (PDEIV) and Rho-kinase in exogenous hydrogen sulfide (H2S)-induced relaxation in mouse corpus cavernosum.MethodsThe relaxant response to H2S (NaHS as exogenous H2S; 1-1000 μM) were obtained in isolated mouse corpus cavernosum tissues which pre-contracted by phenylephrine (5 μM). The effects of 4-(4-octadecylphenyl)-4-oxobutenoic acid (OBAA; 10 μM), a selective phospholipase A2 (PLA2) inhibitor, indomethacin (1 μM), a non-selective cyclooxygenase (COX) inhibitor, baicalein (10 μM), a lipoxygenase (LOX) inhibitor, and proadifen (10 μM), cytochrome P450 inhibitor, on the relaxant responses to H2S were investigated. Furthermore, the effects of theophylline (500 μM) and rolipram (1 μM), a non-selective and selective PDEIV inhibitor, and fasudil (3 μM), a specific Rho-kinase inhibitor, were studied on H2S-induced relaxation.ResultsH2S-induced relaxations were significantly reduced by OBAA, indomethacin and proadifen but not baicalein. Furthermore, theophylline, rolipram and fasudil reduced H2S-induced relaxations.ConclusionThese results suggest that PLA2, COX, cytochrome P450, PDEIV and Rho-kinase pathway may involve in H2S-induced relaxation in mouse corpus cavernosum tissues.