Pharmacological profile of a nitric oxide donor spermine NONOate in the mouse corpus cavernosum

Background/aim: To investigate the effects of spermine NONOate in the cavernous tissue obtained from mice treated or untreated with sildenafil. Materials and methods: We studied the effects of spermine NONOate on the tone and nitrergic relaxation responses of isolated mouse corpus cavernosum and compared them with sodium nitroprusside in the absence or presence of L-nitroarginine, hydroxocobalamin, pyrogallol, diethyldithiocarbamate (DETCA), or 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). The neurogenic contractions and relaxations of the tissues were induced by electrical field stimulation. Some mice received a single oral dose of sildenafil and after 1 h the effects of spermine NONOate were evaluated by in vitro studies. Results: Spermine NONOate relaxed mouse corpus cavernosum in a concentration-dependent manner. Spermine-NONOate-induced relaxation was relatively slow to develop and it was reversible and reproducible. These relaxations were significantly suppressed by hydroxocobalamin, diethyldithiocarbamate, or ODQ, but not by L-nitroarginine or pyrogallol. Spermine NONOate potentiated the nitrergic relaxations to electrical field stimulation (EFS), whereas it significantly reduced EFS-induced contractions. Sildenafil treatment can enhance the relaxant responses to spermine NONOate and EFS. Conclusion: These findings suggest that spermine NONOate has a potent relaxant action in cavernous tissue and this effect can be potentiated by oral sildenafil treatments. Spermine NONOate may be considered an attractive treatment for erectile dysfunction in pathologic disorders with a lack of endogenous NO production.