Comparison of the effects of various anticholinergic drugs on human isolated urinary bladder.

Abstract

We investigated the effects of various anticholinergic drugs (atropine, oxybutynin, terodiline and propiverine) on the contractions induced by acetylcholine, KCl, CaCl2, and electrical field stimulation, in human isolated urinary bladder smooth muscles using the muscle bath technique. Urinary bladders were obtained from 20 patients who underwent total cystectomy due to malignant bladder tumor. The detrusor preparations were taken from the intact part of the dome of the bladder. Acetylcholine caused a concentration-dependent contraction in human detrusor preparations. Atropine (10(-9)-10(-6) M), oxybutynin (10(-8)-10(-5) M), terodiline (10(-7)-10(-5) M) and propiverine (10(-7)-10(-5) M) caused parallel shifts to the right of the concentration-response curves to acetylcholine. The rank order of pA2 values was: atropine > oxybutynin > terodiline = propiverine. Atropine did not suppress the maximum contraction to acetylcholine, while the other drugs significantly suppressed the maximum contractions at the higher concentrations. Each drug caused a concentration-dependent inhibition of the KCl (80 mM)- and CaCl2 (5 mM)-induced contractions; the maximum inhibitions of terodiline and propiverine were significantly greater than those of oxybutynin and atropine. Each drug caused a concentration-dependent inhibition of the contraction induced by electrical field stimulation; the maximum inhibitions of terodiline and propiverine were significantly greater than those of oxybutynin and atropine. The results suggest that the drugs have both anticholinergic and calcium antagonistic effects. Furthermore, it also appears that part of the human bladder contraction, which was significantly inhibited by terodiline and propiverine, is an atropine-resistant component.