Abstract
In the previous reports Takagi and Takayanagi (1-5) have speculated that with regard to the liberation of acetylcholine from the guinea pig ileum, two mechanisms can be responsible; the first is important at low frequencies of electrical stimulation and is concerned with the action of 5-hydroxytryptamine, picric acid and nicotine and is depressed by morphine and strychnine but the nerve path way concerned with 5-hydroxytryptamine may be different from that concerned with nicotine (or dimethylphenyl piperazinium) in this mechanism (6, 7); the second is induced at high frequencies of electrical stimulation and by the action of phenyl acetate and is resistant to the inhibitory action of morphine and strychnine. However, it has been recently reported by Bowman and Hemsworth (8) that triethyl(2-hydroxyethyl)ammonium (or triethylcholine) depresses contractions of the isolated phrenic nerve-hemidiaphragm preparation of the rat and choline restores the contractions depressed by triethylcholine. So in this paper modes of action of trimethyl(2-hydroxyethyl)ammonium chloride (or choline), ethyldimethyl(2-hydroxyethyl)ammonium iodide, methyldiethyl(2-hydroxyethyl)ammonium iodide, propyldimethyl (2-hydroxyethyl)ammonium iodide, triethyl(2-hydroxyethyl)ammonium iodide (or triethylcholine), propyldiethyl(2-hydroxyethyl)ammonium iodide and benzyldimethyl(2-hydroxyethyl)ammonium chloride on the isolated guinea pig ileum were investigated.
