COMPARISON OF THE EFFECTS OF VARIOUS ANTICHOLINERGIC DRUGS ON HUMAN ISOLATED URINARY-BLADDER

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 hum an isolated urinary bladder smooth muscles using the muscle bath techn ique. Urinary bladders wore obtained from 20 patients who underwent to tal cystectomy due to malignant bladder tumor. The detrusor preparatio ns were taken from the intact part of the dome of the bladder. Acetylc holine 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 c urves to acetylcholine. The rank order of pA(2) values was: atropine > oxybutynin > terodiline = propiverine. Atropine did not suppress the maximum contraction to acetylcholine, while the other drugs significan tly suppressed the maximum contractions at the higher concentrations. Each drug caused a concentration-dependent inhibition of the KCl (80 m M)- and CaCl2 (5 mM)-induced contractions: the maximum inhibitions of terodiline and propiverine were significantly greater than those of ox ybutynin and atropine. Each drug caused a concentration-dependent inhi bition 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 tha t the drugs have both anticholinergic and calcium antagonistic effects . Furthermore: it also appears that part of the human bladder contract ion. which was significantly inhibited by terodiline and propiverine, is an atropine-resistant component.