Introduction: Ginseng is an herbal medicine with a variety of biological activities.
Aim: The purpose of this study was to investigate the effect of Korean red ginseng (KRG) extract on the relaxation response in isolated rabbit vaginal tissue and its mechanism as a potential therapeutic agent for female sexual dysfunction.
Method: Strips of rabbit vagina were mounted in organ chambers to measure isometric tension. After the strips were precontracted with phenylephrine, the contractile responses to KRG extract (1-20 mg/mL), nitric oxide inhibitor (N[omega]-nitro-L-arginine methyl ester [L-NAME]), an inhibitor of soluble guanylate cyclase (methylene blue), an inhibitor of Ca(2+)-activated K(+) channels (tetraethylammonium [TEA]), and an adenosine triphosphate (ATP)-sensitive K(+) channel blocker (glybenclamide) were examined.
Main outcome measures: The relaxation of the vaginal tissue strip was assessed after treating KRG extract or other chemicals.
Results: KRG (1-20 mg/mL) extract relaxed the vaginal tissue strip in a dose-dependent manner up to 85%. The relaxation effect was significantly inhibited by L-NAME (30 microM) and methylene blue (30 microM) (P < 0.05). In addition, KRG inhibited the contraction induced by depolarization with 10, 20, and 40 mM KCl. The KRG-induced relaxation effect was significantly inhibited by TEA (300 microM) (P < 0.05), and not by glybenclamide (30 microM).
Conclusions: These data show that KRG extract has a relaxing effect on rabbit vaginal smooth muscle tissue. These effects might be mediated partly through the NO pathway and hyperpolarization via Ca(2+)-activated K(+) channels.