Catalepsy induced by morphine or haloperidol: effects of apomorphine and anticholinergic drugs.
To investigate the extent of cholinergic involvement in opiate-induced catalepsy, the effects of three anticholinergic drugs were studied on morphine-induced catalepsy. Haloperidol-induced catalepsy was also examined. Maximum catalepsy in rats was obtained with 30 mg/kg morphine or 3 mg/kg haloperidol. The anticholinergic drugs atropine, benztropine, and scopolamine were unable to antagonize morphine-induced catalepsy, yet readily antagonized haloperidol-induced catalepsy. Low doses of apomorphine (7.5 mg/kg), on the other hand, readily antagonized morphine catalepsy, but 13-fold higher doses of apomorphine were needed to block haloperidol-induced catalepsy. The results are compatible with the idea that catalepsy can be mediated via the striatum or the amygdala; morphine-dopamine antagonism may occur in the amygdala, whereas morphine-dopamine-cholinergic interactions occur in the striatum.
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001058:Apomorphine / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology; D001590:Benztropine / Q000494:pharmacology; D002375:Catalepsy / Q000139:chemically induced*; D004347:Drug Interactions; D006220:Haloperidol / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D012601:Scopolamine / Q000494:pharmacology; D013997:Time Factors
D014150:Antipsychotic Agents; D001590:Benztropine; D009020:Morphine; D001285:Atropine; D012601:Scopolamine; D006220:Haloperidol; D001058:Apomorphine