An aqueous extract of Coptis chinensis (ACC) augments rat penile tissue erection

Abstract

The aim of the present study was to investigate whether an aqueous extract of Coptis chinensis (ACC) augments penile erection in vivo and in ex vivo. In isolated endothelium‐intact rabbit corpus cavernosum preconstricted with phenylephrine, ACC (10−7−10−4 g/ml) relaxed penile smooth muscle in a dose‐dependent manner, which was inhibited by pretreatment with a nitric oxide synthase inhibitor, and a soluble guanylyl cyclase (sGC) inhibitor, respectively. In addition, incubation of endothelium intact rabbit corpus cavernosum tissues with ACC increased cGMP production in a dose‐dependent manner. ACC‐induced cGMP production was not blocked by pretreatment with L‐NAME or ODQ. Moreover, IBMX, a non‐selective phosphodiesterase (PDE) inhibitor, or zaprinast, a type 4, 5‐selective PDE inhibitor caused more increase in cGMP production than ACC alone. On the other hand, there are no significant difference between increases in penile tissue cGMP production induced ACC and co‐treated with ACC and IBMX or zaprinast, respectively. ACC (100, 500 mg/kg) also caused increase in intracavernous pressure and area under the curve in rats in a dose dependent manner. These results suggest that ACC maybe induce penile erection through the activation of penile tissue NO/cGMP system and/or inhibition of PDE in rat corpus cavernosum.