Acetylcholine, a New Active Principle of Ergot

Investigations carried out during the past few years have resulted in the isolation from ergot of several active principles, the presence of which adequately accounts for those actions of the drug which have been regarded as specially related to its therapeutic effects, each type of action having been advocated by one observer or another as a basis for its physiological standardisation.The principles in question are (1) the alkaloid ergotoxine C,,H,4106N5(the hydroergotinine of Kraft [1906]) which was isolated by Barger and Carr [1907] and further investigated by Barger and Ewins [1910];(2) p. hydroxyphenylethylamine, OH .C8H4.CH2.CH2.NH2 [Barger 1909;Barger and Dale 1909], and (3) 18-iminazolylethylamine HIC:N\ HC :\C *-CH *-CH2 NEI2 NH .CH[ Barger and Dale 1910], the last two beirng amines derived respectively fiom the amino-acids tyrosine and histidine by decarboxylation.In addition, however, to those of apparent therapeutic importance, certain other effects are shown in a more or less marked degree by all samples of the drug and by some with marked intensity.These effects have been familiar to the pharmacological workers in these laboratories for some years, but apparently have not been the subject of exact description or investigation.Conspicuous among these is an inhibitor effect on the heart, suggesting an intense though curiously evanescent muscarine action.Finding that the prominence of this effect in the action of different specimens of ergot ran closely parallel with their stimulant action on intestinal muscle, and that both effects were abolished by atropine, Dr Dale was led to suspect the presence in ergot of a principle producing both these effects.He was also able to