Effects of diacetyl monoxime on neuromuscular transmission.

The action of diacetyl monoxime on neuromuscular transmission has been studied in frogs, chickens, and cats, and in isolated rat phrenic nerve-diaphragm preparations. In frogs and chickens the oxime caused a flaccid paralysis; in chickens there was sometimes opisthotonos. In the indirectly stimulated rat diaphragm, diacetyl monoxime decreased the height of a single twitch, but a tetanus was well sustained. In cats, the twitch height of the indirectly excited gastrocnemius-soleus muscle was reduced by diacetyl monoxime more than was that of the tibialis anterior muscle, but in both muscles a tetanus was well maintained. Diacetyl monoxime reduced the response to direct stimulation of both the rat diaphragm and cat muscles. Diacetyl monoxime injected intra-arterially in the cat elicited a transient hypertension and a gasp. Diacetyl monoxime did not reverse the neuromuscular block caused by anticholinesterases either in isolated rat phrenic nerve-diaphragm preparations or in cats.