THE ACTION OF CHOLINE AND RELATED COMPOUNDS ON THE HEART. OF VENUS MERCENARIA

Abstract

1. A method of preparing and employing the isolated heart of the quahog, Venus mercenaria, for the bio-assay of acetylcholine (Ach) is described. 2. The activities of choline and certain choline esters; of betaine and its ethyl ester; and of triethylcholine and triethyl-acetylcholine on the isolated Venus heart are compared. In further understanding the fundamental mode of action of Ach, the most significant observation was that the substitution of ethyl groups for methyl on the nitrogen of choline and Ach resulted in a complete loss of activity determined by observation on the amplitude of heart beat.