Behavioural subsensitivity induced by long-term administration of a low dose of haloperidol to rats.
This study examines the effects on open-field and stereotyped behaviour of rats of abrupt withdrawal from repeated treatment with a low (0.03 mg kg-1) dose of haloperidol. Single administration of this low dose of haloperidol significantly increased open-field locomotion without modifying apomorphine (0.5 or 2.0 mg kg-1)-induced stereotyped behaviour. Forty-eight hours after abrupt withdrawal from 0.03 mg kg-1 haloperidol (twice daily for 15 days) a significant decrease in locomotion frequency was observed, but no change was observed in apomorphine-induced stereotypy. Our results suggest that dopamine autoreceptor supersensitivity might be evaluated in a behavioural situation of absence of postsynaptic dopamine receptor supersensitivity.
Frussa-Filho
R
R
Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
Abílio
V C
VC
Bergamo
M
M
Palermo-Neto
J
J
D000284:Administration, Oral; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D017660:Autoreceptors / Q000187:drug effects / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects*; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D004347:Drug Interactions; D006220:Haloperidol / Q000008:administration & dosage / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013239:Stereotyped Behavior / Q000187:drug effects*; D013375:Substance Withdrawal Syndrome
D017660:Autoreceptors; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D006220:Haloperidol; D001058:Apomorphine