Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

• Published in: Asian journal of andrology Vol. 15; no. 1; pp. 134 - 137
• Main Authors: Sun, Kai, Zhao, Chen, Chen, Xiang-Feng, Kim, Hye-Kyung, Choi, Bo-Ram, Huang, Yi-Ran, Park, Jong-Kwan
• Format: Journal Article
• Language: English
• Published: China Medknow Publications & Media Pvt. Ltd 01.01.2013; Nature Publishing Group
• Subjects: Animals; Cuscuta - chemistry; Cyclic GMP - physiology; Enzyme Inhibitors - pharmacology; Erectile Dysfunction - drug therapy; Herb-Drug Interactions; Male; Muscle Relaxation - drug effects; Muscle, Smooth - drug effects; NG-Nitroarginine Methyl Ester - pharmacology; Original; Penile Erection - drug effects; Penis - drug effects; Penis - physiology; Phytotherapy; Piperazines - pharmacology; Plant Extracts - pharmacology; Purines - pharmacology; Rabbits; Sildenafil Citrate; Sulfones - pharmacology; 一氧化氮合成酶; 提取物; 新西兰白兔; 松弛; 枸橼酸西地那非; 浓度依赖性; 菟丝子; 阴茎海绵体
• ISSN: 1008-682X; 1745-7262
• DOI: 10.1038/aja.2012.124

The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum （PCC） was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits （2.5-3.0 kg） were precontracted with phenylephrine （Phe, 10 pmol I^-1） and then treated with various concentrations of Cuscuta chinensis extract （1, 2, 3, 4 and 5 mg ml^-1）. The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay （RIA）. The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase （NOS） inhibitor （No〉 nitro-L-arginine-methyl ester, L-NAME）, a guanylyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-l-one, ODQ）, or a protein kinase A inhibitor （KT 5720） did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate （cGMP） and cyclic adenosine monophosphate （cAMP） in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction （ED）, which does not completely respond to sildenafil citrate.