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Asian Journal of Andrology (2013) 15, 134–137; doi:10.1038/aja.2012.124; published online 12 November 2012
Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum
Kai Sun1,*, Chen Zhao1,*, Xiang-Feng Chen1, Hye-Kyung Kim2, Bo-Ram Choi2, Yi-Ran Huang1 and Jong-Kwan Park2
1 Department of Urology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, and Shanghai Institute of Andrology, Shanghai 200127, China
2 Department of Urology, Chonbuk National University, and Research Institute of Clinical Medicine and Clinical Trial Center of Medical Device of Chonbuk National University Hospital, Jeonju 561-712, South Korea
Correspondence: Dr YR Huang, (hyrrenji2@yahoo.com.cn); Dr JK Park, (rain@jbnu.ac.kr)
* These authors contributed equally to this work.
Received 24 July 2012; Revised 23 August 2012; Accepted 10 October 2012
Advance online publication 12 November 2012
| Abstract |
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 µmol l−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 (Nω nitro-L-arginine-methyl ester, L-NAME), a guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-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.
Keywords: Cuscuta chinensis; erectile dysfunction (ED); NO-cGMP pathway; penile corpus cavernosum (PCC); sildenafil |
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