Penile erectile responses to electric stimulation are enhanced by a new phosphodiesterase type-5 inhibitor

Aim: This study was conducted to investigate the effect of DA-8159, a new phosphodiesterase type-5 (PDE5) inhibitor, on electrostimulation-induced penile erection in rats. Methods: Intracavernous pressure (ICP) and arterial blood pressure (BP) were simultaneously recorded through electric pelvic-ganglion stimulation (2–10 Hz) after the oral administration of DA-8159 (3 or 10 mg/kg) in normal and streptozotocin-induced diabetic rats. Statistical analysis was performed on the maximal intracavernous pressure (ICP), detumescence time, maximal intracavernous pressure/blood pressure (ICP/BP) ratio, and the area under the curve (AUC) of the ICP/BP ratio. Results: In normal and diabetic rats, electrical stimulation of the pelvic ganglion induced a frequency- and dose-dependent increase in the intracavernous pressure. The ICP/BP ratio and the corresponding AUC values were also significantly and dose-dependently increased after DA-8159 administration. In addition, the detumescence time significantly increased after DA-8159 administration compared to that of the controls. Conclusions: These results show that the DA-8159 significantly increased the intracavernous pressure response and prolonged the decay period induced by electrical stimulation of the pelvic ganglion, and suggest that DA-8159 might be a potential therapeutic agent for the treatment of erectile dysfunction.