[Excito-motor action of succinyldicholine and inhibitory action of acetylcholine on slow muscle, the frog hypoglossus].

We have registered contraction of the frog's hyoglossus which is essentially slow. By injecting succinyldicholin in the heart ventricle, we have elicited contractions which prove definitively the motor effect of this cholin ester on the slow muscular fibers. Acetylcholin, injected in the lymph vessels to avoid its effect on the heart, does not contract the hyoglossus. On the contrary, by exciting electrically the hypoglossus nerve, which commands the hyoglossus, we have observed that this mono-ester abolishes the neuro-muscular transmission, as in the curare intoxication. We have found the same phenomenon on the rat's semi-tendinosus which is a slow muscle too. The twitches produced by the ischiaticus are diminished significantly after the injection of acetylcholin in the jugular vein.