COMPARATIVE PHARMACOLOGICAL STUDY OF THE MONO AND DICHOLINE ESTERS OF SUCCINIC ACID

The probable first hydrolysis product of succinyldicholine, the monocholine ester of succinic acid, has been studied and its actions have been compared with those of the dicholine ester. 1. The monoester has markedly less myoneural blocking action than the diester. In adequate doses, however, myoneural blockade does take place. This blockade is longer lasting and slower both in onset and recovery than the response from succinyldicholine. 2. The blocking action of the monoester is reduced by No. 49-204, a substance which antagonizes decamethonium, whereas that of the dicholine ester is not. No. 51-212 antagonizes the blocking action of the monoester as it does that of succinyldicholine and decamethonium. 3. No. 50-354 prolongs the blocking action of succinylmonocholine, succinyldicholine and decamethonium. 4. A slight depressor action was found for the monocholine ester which has not been seen with the dicholine ester. Repeated doses show a weakening of the depressor action, and after several doses, the response becomes pressor. 5. The monocholine ester is less toxic than succinyldicholine, but the symptoms are qualitatively similar.