Gj. Amabeoku, SOME BEHAVIORAL-EFFECTS OF CHLOROQUINE IN RATS SUGGESTING DOPAMINERGIC ACTIVATION, INDIAN JOURNAL OF MEDICAL RESEARCH, 99, 1994, pp. 87-94
The effect of chloroquine on open-field behaviour, apomorphine induced
stereotypies and haloperidol and pimozide-induced catalepsy was studi
ed in rats. Chloroquine (2.5-10 mg/kg, ip) significantly increased the
locomotion frequently of rats in the open-field and also markedly enh
anced apomorphine (0.4 mg/kg, sc)-induced locomotion. Haloperidol (0.2
5 mg/kg, ip) antagonised the increased locomotion frequency produced b
y chloroquine (5mg/kg, ip), apomorphine (0.4mg/kg, sc) and chloroquine
plus apomorphine. L-Dopa (50mg/kg, sc) and benserazide (12.5mg/kg, ip
) plus L-Dopa (50mg/kg, sc) significantly increased chloroquine (5mg/k
g, ip)-induced locomotion. SCH 23390 (0.2mg/kg, sc) and sulpiride (30m
g/kg, ip), on the other hand, attenuated chloroquine (5mg/kg, ip)-indu
ced locomotion. Chloroquine (2.5-5mg/kg, ip) elicited stereotyped beha
viour in rats and significantly potentiated apomorphine (2mg/kg, sc)in
duced stereotypies. Haloperidol (0.25mg/kg, ip) markedly reduced the s
tereotypies produced by both chloroquine (5mg/kg, ip) and apomorphine
(2mg/kg, sc). Both chloroquine (2.5-10mg/kg, ip) and apomorphine (0.4m
g/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 m
ay be involved in the observed effects of chloroquine.