The effect of 2-n-propyl-3-dimethylamino-5,6-methylenedioxyindene on caffeine-induced contractures of skeletal muscle.

It has been previously postulated that 2-n-propyl-3-dimethylamino-5,6-methylenedioxyindene (pr-MDI) exhibits calcium antagonistic properties with an intracellular site of action. The present investigation further substantiates this hypothesis by providing evidence that pr-MDI inhibits caffeine-induced contractures (which are mediated by intracellular calcium) of the isolated rat hemidiaphragm skeletal muscle both in the presence and in the absence of extracellular calcium.