Sildenafil relaxes rabbit clitoral corpus cavernosum

The role of phosphodiesterase type 5 inhibition in the modulation of female sexual dysfunction was investigated by assessing its effects on in vitro r elaxation of rabbit clitoris. Stimulation of the nonadrenergic, non-choline rgic neurons of the clitorus elicited a frequency-dependent relaxation resp onse. inhibition of NO synthase with L-NAME (100 mu M) or inhibition of sol uble guanylate cyclase with ODQ (1.0 mu M) almost completely abolished the electrical field stimulation-induced relaxation of clitorus suggesting that NO-cGMP pathway mediates the relaxation response to electrical field stimu lation. Similarly, tetrodotoxin, a neuronal sodium channel blocker abolishe d the electrical field stimulation-induced clitoral relaxation implying a n euronal release of NO contributes to the electrical field stimulation elici ted relaxation. Pretreatment of the clitoral corpus cavernosum strips with sildenafil (100 nM) enhanced the electrical field stimulation-induced relax ations both in magnitude and duration. The results suggest that sildenafil enhances electrical field stimulation elicited clitoral relaxation by a NO- cGMP dependent pathway. These data also imply that sildenafil may be useful to treat female sexual dysfunction, (C) 2000 Elsevier Science Inc. All rig hts reserved.