ABSTRACT
PURPOSE: Relaxation of the penile cavernosum smooth muscle is a critical event in erection. Artemisia iwaymogi(AI) is a perennial herb growing in Korea. The aerial parts have been used in folk medicine. Bioassay-guided fractionation of an H2O extract of AI has furnished an inhibitory substance (PCLS-2). We investigated compound extracted in the rabbit corporal cavernosum smooth muscle. MATERIALS AND METHODS: Bioassay-guided fractionation of an H2O extract was used. A strip of rabbit corpus cavernosum was mounted in an organ chamber to measure the isometric tension. PCLS-2 compound induced relaxations were evaluated by in vitro study using muscarinic receptor blocker atropine (ATR), cyclo-oxygenase inhibitor indomethacin, nitric oxide synthase (NOS) ihibitor Nitro-L Arginine-Methyl Ester (NAME), guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin 1-one (ODQ), intrinsic neurotransmission inhibitor tetrodotoxin (TTX), or/and potassium channel blockers. RESULTS: PCLS-2 showed relaxation in a dose-dependent manner. Atropine, Indomethacin, NAME, ODQ, TTX, glibenclamide, tetraethylammonium, 4-aminopyridine, charybdotoxin, or apamin did not inhibit the relaxation induced by PCLS-2 compound. CONCLUSIONS: The present results suggest that the PCL-2 compound has effect of relaxation of corpus cavernosum smooth muscle and the relaxation was not involved muscarinic receptor, nitric oxide, prostaglandin, potassium channels and intrinsic neurotransmission. Other mechanisms may by involved in the PCLS-2 induced relaxation in the rabbit corpus cavernosum smooth muscle.