Fig. 1.
Effects of melatonin pretreatment (10-8~10-6 M) on the concentration-response curve for phenylephrine (109~10-4 M) and acetylcholine (10-9~10-4 M) in Sprague-Dawley rat detrusor smooth muscles. (A) Pretreatment with melatonin dose-dependently decreased the contractile responses induced by phenylnephrine (n=8 in each). (B) Melatonin blocked acetylcholine-induced contractions, which were stronger than phenylnephrine contractions (n=12 in each). Asterisk means p<0.05. Each point represents the mean±standard error of means (SEM); if the SEMs were not shown, the bars fall within the size of the symbols.