Effects of continuous exposure to light on behavioral dopaminergic supersensitivity

Effects of continuous exposure to light on behavioral dopaminergic supersensitivity

Author Abilio, V. C. Google Scholar
Freitas, F. M. Google Scholar
Dolnikoff, M. S. Google Scholar
Castrucci, AML Google Scholar
Frussa, R. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Background: This study examines the effects of long-term continuous exposure to light on dopaminergic supersensitivity induced by repented treatment with haloperidol in rats,Methods: Spontaneous general activity in an open-field (SGA) and stereotyped behavior induced by apomorphine (SB-APO) or amphetamine (SB-AMP) were used as experimental parameters. Rats were allocated to four groups in each experiment: saline-treated animals kept under a 12-hour light/dark cycle (LD) or 24-hour light/light cycle (LL), and 2 mg/kg haloperidol-treated animals kept under the above cycles. Plasma corticosterone concentration was also measured by radioimunoassay in saline-treated mts kept under a LD or LL cycle.Results: All the behavioral parameters used showed the development of central dopaminergic supersensitivity in rats kept under both cycles. Continuous exposure to light enhanced SGA and SB-AMP in both saline- and haloperidol-treated mts, but did not modify SB-APO. Animals kept under the LL cycle presented an increased plasma corticosterone concentration.Conclusions: Our results suggest that continuous exposure to light leads to an increase in dopaminergic function in both normal and supersensitive rats. This effect seems to be mediated by a presynaptic mechanism possibly involving corticosterone actions. (C) 1999 Society of Biological Psychiatry.
Keywords light
melatonin
dopamine
stress
rat
behavior
Language English
Date 1999-06-15
Published in Biological Psychiatry. New York: Elsevier B.V., v. 45, n. 12, p. 1622-1629, 1999.
ISSN 0006-3223 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 1622-1629
Origin http://dx.doi.org/10.1016/S0006-3223(98)00305-9
Access rights Closed access
Type Article
Web of Science ID WOS:000080845000013
URI http://repositorio.unifesp.br/handle/11600/26095

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