Some behavioural effects of chloroquine in rats suggesting dopaminergic activation.
The effect of chloroquine on open-field behaviour, apomorphine induced stereotypies and haloperidol and pimozide-induced catalepsy was studied in rats. Chloroquine (2.5-10 mg/kg, ip) significantly increased the locomotion frequently of rats in the open-field and also markedly enhanced apomorphine (0.4 mg/kg, sc)-induced locomotion. Haloperidol (0.25 mg/kg, ip) antagonised the increased locomotion frequency produced by chloroquine (5 mg/kg, ip), apomorphine (0.4 mg/kg, sc) and chloroquine plus apomorphine. L-Dopa (50 mg/kg, sc) and benserazide (12.5 mg/kg, ip) plus L-Dopa (50 mg/kg,sc) significantly increased chloroquine (5 mg/kg, ip)-induced locomotion. SCH 23390 (0.2 mg/kg, sc) and sulpiride (30 mg/kg, ip), on the other hand, attenuated chloroquine (5 mg/kg, ip)-induced locomotion. Chloroquine (2.5-5 mg/kg, ip) elicited stereotyped behaviour in rats and significantly potentiated apomorphine (2 mg/kg, sc)-induced stereotypies. Haloperidol (0.25 mg/kg, ip) markedly reduced the stereotypies produced by both chloroquine (5 mg/kg, ip) and apomorphine (2 mg/kg, sc). Both chloroquine (2.5-10 mg/kg, ip) and apomorphine (0.4 mg/kg, sc) significantly delayed the onset and decreased the intensity of catalepsy induced by haloperidol (0.25mg/kg, ip) and pimozide (2mg/kg, ip) respectively. These findings indicate that chloroquine, in low doses, produces excitatory effects and that dopaminergic mechanisms may be involved in the observed effects of chloroquine.
Amabeoku
G J
GJ
Department of Clinical Pharmacology, Medical School, University of Zimbabwe, Harare.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D002375:Catalepsy / Q000139:chemically induced; D002738:Chloroquine / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011954:Receptors, Dopamine / Q000187:drug effects*; D013239:Stereotyped Behavior / Q000187:drug effects
D011954:Receptors, Dopamine; D002738:Chloroquine; D001058:Apomorphine