Some pharmacological effects of the nematocide, morantel.

1. In isolated nerve-muscle preparations as well as in nerve-muscle preparations in intact anaesthetized animals, morantel exhibited neuromuscular blocking properties similar to those of depolarizing blockers. The drug also caused spastic paralysis of 3 day-old chicks and contracture of the isolated toad rectus abdominis muscle.2. Morantel caused contraction of the guinea-pig and rabbit isolated small intestine. This effect was antagonized by atropine and hexamethonium.3. Morantel caused an increase in the blood pressure of the anaesthetized rat and cat and contraction of the nictitating membrane of the anaesthetized cat. These effects were antagonized by hexamethonium.4. It was concluded that morantel (like the related compound pyrantel) has acetylcholine-like action and that its structure is consistent with such action.