The role of monoamines for the central effects of Baclofen on behavior of rats.
Male albino rats given a bilateral injection of Baclofen (Lioresal) (12 micrograms/rat) in the cerebral ventricles showed a behavioral syndrome of activation + ataxia, paddling, tail-pinch hyperresponse and anesthesia. The phase of activation + ataxia was reduced by pretreatment of rats with H 44/68, FLA 63, reserpine, pimozide, phenoxybenzamine, oxypertine or chlorpromazine. The phase of paddling was reduced by pretreatment with FLA 63, reserpine, phenoxybenzamine, oxypertine, chlorpromazine, pimozide + phenoxybenzamine or apomorphine, while administration of clonidine instead of Baclofen caused paddling in non-pretreated rats. The phase of tail-pinch hyperresponse was reduced by reserpine, oxypertine, chlorpromazine or pimozide + phenoxybenzamine, while none of the pretreatments affected Baclofen-induced anesthesia. Drugs which affect mainly tryptaminergic or GABA-ergic functions failed to affect Baclofen-induced behaviors consistently. The findings suggest that dopaminergic and noradrenergic functions play a role in the central effects of Baclofen on behavior of rats.
D000758:Anesthesia; D000818:Animals; D001259:Ataxia / Q000139:chemically induced; D001418:Baclofen / Q000008:administration & dosage / Q000494:pharmacology*; D002395:Catecholamines / Q000502:physiology; D003000:Clonidine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009638:Norepinephrine / Q000502:physiology; D051381:Rats
D002395:Catecholamines; D001418:Baclofen; D003000:Clonidine; D004298:Dopamine; D009638:Norepinephrine