Erectogenic effect of the selective phosphodiesterase type 5 inhibitor, DA-8159

DA-8159, a new phosphodiesterase 5 inhibitor, was assessed for its erectoge nic potential by a penile erection test in rats, the relaxation of isolated rabbit corpus cavernosum (CC), and estimation of the intracavernous pressu re (ICP) in the anesthetized dog. Oral administration of DA-8159 (0.3 to 1 mg/kg) increased the number of erections in rats with increasing dosage, wi th the highest penile erection index at 10 mg/kg. DA-8159 induced the relax ation of phenylephrine (PHE)-induced contractions in the rabbit CC and decr eased the IC50 of the nitric oxide donor sodium nitroprusside (SNP) in a do se-dependent fashion. In pentobarbital-anesthetized dogs, the intravenous a dministration of DA-8159 (1 similar to 300 mug/kg) potentiated the increase in ICP induced by the intracavernosal SNP in a dose-related manner. These findings suggest that DA-8159 has significant therapeutic potential in the treatment of erectile dysfunction.