The percentage of relaxation induced by Cuscuta chinensis extract in a perfusion model (n=8). The penile cavernosum tissue was precontracted with Phe (10 µmol l−1) and treated with four concentrations of Cuscuta chinensis. The relaxation was dose-dependent. Pre-treatment with L-NAME, ODQ or KT 5720 did not completely abolish the relaxation. The maximal penile contractile responses induced by Phe were taken as the 100% values, and all subsequent responses to Cuscuta chinensis were expressed as a percentage of this value. Each point represents the mean±s.d. of the percentages. L-NAME, Nω nitro-L-arginine-methyl ester; ODQ, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; Phe, phenylephrine.