The role of arachidonic acid/cyclooxygenase cascade, phosphodiesterase IV and Rho-kinase in HS-induced relaxation in the mouse corpus cavernosum.

BACKGROUND

Penile 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 (HS)-induced relaxation in mouse corpus cavernosum.

METHODS

The relaxant response to HS (NaHS as exogenous HS; 1-1000μM) were obtained in isolated mouse corpus cavernosum tissues which pre-contracted by phenylephrine (5μM). The effects of 4-(4-octadecylphenyl)-4-oxobutenoic acid (OBAA; 10μM), a selective phospholipase A (PLA) inhibitor, indomethacin (1μM), a non-selective cyclooxygenase (COX) inhibitor, baicalein (10μM), a lipoxygenase (LOX) inhibitor, and proadifen (10μM), cytochrome P450 inhibitor, on the relaxant responses to HS were investigated. Furthermore, the effects of theophylline (500μM) and rolipram (1μM), a non-selective and selective PDEIV inhibitor, and fasudil (3μM), a specific Rho-kinase inhibitor, were studied on HS-induced relaxation.

RESULTS

HS-induced relaxations were significantly reduced by OBAA, indomethacin and proadifen but not baicalein. Furthermore, theophylline, rolipram and fasudil reduced HS-induced relaxations.

CONCLUSION

These results suggest that PLA, COX, cytochrome P450, PDEIV and Rho-kinase pathway may involve in HS-induced relaxation in mouse corpus cavernosum tissues.