Neuroleptic antagonism of dyskinetic phenomena.

The bilateral intrastriatal administration of dopamine to guinea pigs pretreated with nialamide-induced dyskinesias characterized by gnawing, biting and licking reactions, acute twisting of the head and neck, whole body or head and neck rocking movements, and a hyperactive state. Hyperactivity was inhibited by the peripheral administration of large doses of many neuroleptic agents, e.g. haloperidol, fluphenazine, but only pimozide and oxiperomide inhibited the other forms of dyskinetic movements. This was not due to a peculiar depressant effect of these agents in the guinea pig since haloperidol was shown to be equipotent to oxiperomide and of greater potency than pimozide both in causing catalepsy and antagonising amphetamine sterotypy...