THE ACTIVITY OF CERTAIN LYCORAMINE DERIVATIVES ON MUSCLE

¹ National Institute of Neurological Diseases and Blindness, National Institutes of Health, U. S. Department of Health, Education, and Welfare, Bethesda, Maryland

The muscle potentiating activity of the dimethyl-carbamate of deoxy-demethyl-lycoramine methiodide (MCDL) and the hydrochloride of the same compound (HCDL) has been investigated. At molar equivalent doses MCDL produces a greater amount of muscle potentiation than neostigmine bromide. HCDL is more potent than physostigmine salicylate but has only one-fourth the activity of the methiodide.

As inhibitors of acetylcholinesterase the methiodide and the hydrochloride of this lycoramine derivative are of equal potency but are more active than neostigmine or physostigmine.

The dimethyl-carbamate of deoxy-demethyl-lycoramine methiodide is a more effective antagonist to d-tubocurarine than the hydrochloride and is at least as potent as neostigmine. The hydrochloride has nearly the same activity against d-tubocurarine blockade as physostigmine.

No correlation has been found between the ability of the hydrochloride and methiodide to inhibit acetylcholinesterase, to potentiate indirectly stimulated muscle, or to antagonize d-tubocurarine activity. The methiodide to hydrochloride ratio of these properties is about 1:1 for enzyme inhibition, 1:4 for muscle potentiation and 1:8 for the antagonism to d-tubocurarine.