Paramion contracture of the dorsal muscle of the leech during the action of anticholinesterase drugs

Summary

Experiments were staged on the dorsal muscle of the leech (110 tests). High concentrations of paramion relax the acetylcholine contracture of the muscle. Low doses may cause contracture after preliminary eserine or prostigimine (but not nivalin) treatment of the muscle. Eserine concentrations which fail to produce cholinosensitization promote the development of paramion contracture in the presence of acetylcholine. Low concentrations of paramion, an agent usually included in the D-tubocurarine group may cuase an effect similar to that of acetylcholine and intensify the action of the latter, which is characteristic of decamethonium and compounds of the ditilin type.