Effects of continuous exposure to light on behavioral dopaminergic supersensitivity
Effects of continuous exposure to light on behavioral dopaminergic supersensitivity
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DOI:
10.1016/s0006-3223(98)00305-9
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发表时间:
1999-06-15
影响因子:
10.6
通讯作者:
Frussa, R
中科院分区:
文献类型:
--
作者:
Abílio, VC;Freitas, FM;Frussa, R
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.