Search

Tetramethylammonium in small concentrations contracted the longitudinal muscle of the guinea-pig isolated ileum, but had no effect on the peristaltic reflex. However, in high concentrations, it contracted the longitudinal muscle and blocked the peristaltic reflex. Acetylcholine, methacholine, carbachol, eserine and neostigmine antagonized the peristaltic block previously produced by tetramethylammonium. On the other hand, propionylcholine, butyrylcholine, nicotine, pilocarpine, arecoline, histamine and 5-hydroxytryptamine did not remove the peristaltic block. From these experiments, it is concluded that the predominant sites of the depressive effect of tetramethylammonium on the peristalsis are the cholinoceptive ganglia of myenteric plexus subserving the peristaltic reflex of guinea-pig isolated ileum.

After unique injection LiCl enhances, in albino rat, catalepsy induced by arecoline and oxotremorine perhaps by adenylcyclase inhibition and/or decrease of acetylcholine synthesis. After repetitive injection of LiCl during 5 days, this phenomenon is not observable, probably owing to increase of acetylcholine synthesis. After unique injection of LiCl enhances catalepsy induced by dextromoramide, probably on account of cholinergic properties of this drug. In contrast catalepsy induced by morphine or pethidine is suppressed. This constatation would depend on opposite influence upon cerebral neuromediators : lithium diminishing cerebral serotonin and striatal acetylcholine levels and morphine increasing them. After repetitive injections these phenomenons are not observable.