Effects of melatonin on behavioral dopaminergic supersensitivity

Effects of melatonin on behavioral dopaminergic supersensitivity

Author Abilio, V. C. Google Scholar
Vera, JAR Google Scholar
Ferreira, LSM Google Scholar
Duarte, CRM Google Scholar
Martins, C. R. Google Scholar
Torres-Leite, D. Google Scholar
Ribeiro, R. D. Google Scholar
Frussa, R. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract This study examines the effects of melatonin on dopaminergic supersensitivity induced by long-term treatment with haloperidol in rats. Enhancements of spontaneous general activity in an open-field and of stereotyped behavior induced by apomorphine after abrupt withdrawal from long-term treatment with haloperidol were used as experimental parameters for dopaminergic supersensitivity. Experiment 1 was conducted to investigate the effects of melatonin on the development of dopaminergic supersensitivity, and experiment 2 was conducted to investigate the effects of melatonin on the development as well as on expression of dopaminergic supersensitivity. Rats of both experiments were long-term treated with saline or haloperidol concomitant to saline or melatonin. in experiment 1 behavioral observations were performed after abrupt withdrawal from long-term treatment. in experiment 2 behavioral observations were performed 1 hour after an acute injection of saline or melatonin, administered after the abrupt withdrawal from long-term treatment. Both behavioral parameters used showed the development of central dopaminergic supersensitivity in rats treated with haloperidol since 24 hours after abrupt withdrawal. Concomitant treatment with melatonin intensified haloperidol-induced dopaminergic supersensitivity, observed 72 hours after withdrawal. Melatonin treatment per se also induced behavioral supersensitivity evaluated by both open-field and stereotyped behaviors, although it was more fugacious than that presented by haloperidol. Acute treatment with melatonin reverted the enhancement of the haloperidol-induced dopaminergic supersensitivity produced by concomitant long-term treatment with melatonin, as well as melatonin-induced dopaminergic supersensitivity per se. Our results support previous evidence of antidopaminergic effects of melatonin and demonstrate that repeated administration of this hormone modifies the plasticity of behaviors mediated by central dopaminergic systems. (C) 2003 Elsevier Science Inc. All rights reserved.
Keywords melatonin
dopamine
dopaminergic supersensitivity
rat
behavior
Language English
Date 2003-05-16
Published in Life Sciences. Oxford: Pergamon-Elsevier B.V., v. 72, n. 26, p. 3003-3015, 2003.
ISSN 0024-3205 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 3003-3015
Origin http://dx.doi.org/10.1016/S0024-3205(03)00231-5
Access rights Closed access
Type Article
Web of Science ID WOS:000182522400007
URI http://repositorio.unifesp.br/handle/11600/27255

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