The effects of sildenafil after chronic L-NAME administration in male rat sexual behavior

Abstract Ferraz MMD, Quintella SL, Parcial ALN, Ferraz MR. The effects of sildenafil citrate and L-NAME on male rat sexual behaviour. PHARMACOL BIOCHEM BEHAV. Erectile dysfunction (ED) affects up to 50% of men between 40 and 70 years of age. Significant advances in the pharmacological treatment of ED occurred in recent years, most notably the introduction of the first oral selective phosphodiesterase type-5 inhibitor, sildenafil. This study investigated the effectiveness of chronic oral treatment with L-NAME in rats as an experimental model of erectile dysfunction to evaluate new pharmacological agents that affect the sexual response. The effects of chronic oral L-NAME treatment, separately or in combination with sildenafil, on the sexual behaviour of male rats were evaluated. Filtered water was used as a control. Acute administration of L-NAME did not alter the sexual response compared with control, but sildenafil administration facilitated sexual behaviour after acute and chronic administration. Chronic L-NAME treatment inhibited motivational and consummatory measures of male rat sexual behaviour. Sildenafil prevented the inhibitory effects of L-NAME. The present results confirm that chronic oral treatment with a nitric oxide synthase inhibitor may be a relevant peripheral ED model to evaluate the effects of drugs on erectile function of male rats.