EFFECTS OF STRYCHNINE, DERIVATIVES OF PHENYL ACETATE AND CATECHOLAMINES ON CONTRACTION AND ACETYLCHOLINE OUTPUT FROM THE CHOLINERGIC NERVE ENDING OF GUINEA PIG ILEUM

Abstract

Since strychnine in concentrations of 1 to 6 X 10-6 g/ml depressed the contractions induced by 5-hydroxytryptamine, picric acid and nicotine and also inhibited the acetylcholine output and contraction caused by the coaxial stimulation at 0.1 cps, strychnine as well as morphine are supposed to inhibit the acetylcholine liberation from the cholinergic nerve ending of guinea pig ileum. Catecholamines inhibit the acetylcholine output from the cholinergic nerve but do not take part in the inhibitory actions of morphine and strychnine studied in this report. Phenyl propionate, phenyl butyrate and phenyl benzoate are not the competitive inhibitors, but the nonspecific inhibitors to phenyl acetate. Two mechanisms or 2 acetylcholine stores concerned with the acetylcholine liberation from the guinea pig ileum are involved.