[Compared efficacies of somes antispasmodic drugs on the digestive tract and the bladder of the anesthetized dog (author's transl)].

The antispasmodic activity of tiemonium, mebeverine, pitofenone + fenpiverinium association and N-butyl scopolammonium was compared in the anesthetized dog. Strain gauges were fixed on the gastric antro-fundic border, on the pylorus, on the descending duodenum and on the terminal colon. Pressure transducers were connected with water filled small balloons inserted into the gall bladder and the bladder. Five minutes after the intra-venous injection of the drugs, contraction of the smooth musculature was induced by 3 intra-venous injections of BaCl2 (1 mg.kg(-1)) at 3 minutes intervals. The results were expressed as ED50 values (mg.kg(-1)). 2. Tiemonium was the most potent of the 4 antispasmodic drugs. Its ED50 values were very similar for the different organs, ranging from 0.13 +/- 0.022 for the duodenum to 0.31 +/- 0.03 for the bladder. Mebeverine and pitofenone + fenpiverinium association were equipotent but for colon contraction, where mebeverine was more active (ED50 = 0.68 +/- 0.06). Other ED50 relatives to these 2 compounds were ranging from 0.40 +/- 0.02 (duodenum) to 1.32 +/- 0.14 (gall bladder). N-butyl scopolammonium was found to be the weakest antispasmodic drug on this model. Its activity was very weak on colon (ED50 = 5.21 +/- 0.037), gall bladder (ED50 = 5.40 +/- 0.074) and bladder (ED50 = 5.02 +/- 0.059). 3. The strong antispasmodic activity demonstrated on this model with tiemonium seems to be due to its potent inhibition of membrane Ca++ ions, added to its moderate anticholinergic activity.