[Pharmacological studies on antispasmodics. V. Effect of 3-(di-2-thienylmethylene)-5-methyl-trans-quinolizidinium bromide (HSR-902) on the junctional transmission of pelvic nerve ending in isolated urinary bladder (author's transl)].

Effects of HSR-902, a new antispasmodic agent, on the junctional transmission of pelvic nerve ending in isolated urinary bladder was compared with those of atropine sulfate, butylscopolamine bromide, timepidium bromide and prifinium bromide. Tetrodotoxin (3 x 10(-8)g/ml) completely inhibited the contraction of isolated guinea pig urinary bladder induced by transmural stimulation (TM contraction), but hexamethonium chloride (1 x 10(-4)g/ml) and atropine sulfate (1 x 10(-5)g/ml) exhibited no inhibition and a slight inhibition, respectively. Neostigmine bromide (1 x 10(-7)g/ml) increased TM contraction, and the effect was completely inhibited by atropine sulfate (1 x 10(-5)g/ml). Antispasmodic agents (1 x 10(-7) - 1x 10(-5)g/ml), excluding HSR-902, showed slight inhibition on TM contraction. In contrast, HSR-902 (1 x 10(-6) - 1x10(-5)g/ml) increased TM contraction and/or resting tone (1 x 10(-5)g/ml). Phenoxybenzamine hydrochloride (1 x 10(-8)g/ml) and tolazoline hydrochloride (1 x 10(-5)g/ml), alpha-blocking agents, increased both TM contraction and resting tone. Increasing effects of HSR-902 on TM contraction and/or resting tone were completely inhibited by noradrenaline (1 x 10(-5)g/ml) with propranolol hydrochloride (1 x 10(-5)g/ml). These results suggested that these antispasmodic agents scarcely inhibited the junctional transmission in postganglionic cholinergic nerve ending induced by transmural stimulation of isolated guinea pig urinary bladder, and HSR-902 rather increased the transmission. Since it was also suggested that there was alpha-adrenoceptor inhibiting acetylcholine-release in the postganglionic cholinergic nerve terminal, the transmission increasing action of HSR-902 would be due to its alpha-blocking action.