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Short days increase hypothalamic-pituitary-adrenal axis responsiveness.
- Source :
-
Endocrinology [Endocrinology] 2007 Jul; Vol. 148 (7), pp. 3402-9. Date of Electronic Publication: 2007 Mar 29. - Publication Year :
- 2007
-
Abstract
- Individuals dramatically alter physiology and behavior to adapt to seasonal changes in their environment. To cope with winter stressors such as reduced food availability and low temperatures, central stress responses are presumably modulated at the level of the hypothalamic-pituitary-adrenal (HPA) axis, but the details remain unspecified. We examined the effects of long or short photoperiods (day lengths) on corticosterone responses to restraint, HPA negative feedback sensitivity, glucocorticoid receptor gene expression in the hippocampus, the role of corticosterone in spatial learning, and corticosterone responses to stressors associated with the spatial water maze task in adult male white-footed mice (Peromyscus leucopus). Short days increased corticosterone responses to restraint, increased hippocampal glucocorticoid receptor expression, enhanced corticosterone negative feedback on the HPA axis, and increased sensitivity to dexamethasone suppression of corticosterone. Although spatial learning and memory performance (via water maze) of all mice was impaired after pharmacological corticosterone inhibition, both water maze exposure and treatment injections alone were sufficient to increase short-day, but not long-day, corticosterone concentrations. Thus, the effects of corticosterone on spatial learning in these mice may be complicated by photoperiodic differences in stressor response to the learning task itself. Overall, these results suggest that photoperiod-evoked modification of the HPA axis and its potential behavioral consequences may be adaptive for winter survival.
- Subjects :
- Analysis of Variance
Animals
Corticosterone blood
Dexamethasone pharmacology
Gene Expression Regulation drug effects
Gene Expression Regulation radiation effects
Hypothalamo-Hypophyseal System drug effects
Hypothalamo-Hypophyseal System radiation effects
Hypothalamus drug effects
Hypothalamus metabolism
Hypothalamus radiation effects
Male
Maze Learning drug effects
Maze Learning physiology
Maze Learning radiation effects
Memory drug effects
Memory physiology
Memory radiation effects
Mice
Pituitary-Adrenal System drug effects
Pituitary-Adrenal System radiation effects
Radioimmunoassay
Receptors, Glucocorticoid genetics
Receptors, Glucocorticoid metabolism
Sodium Chloride administration & dosage
Sodium Chloride pharmacology
Spatial Behavior drug effects
Spatial Behavior physiology
Spatial Behavior radiation effects
Hypothalamo-Hypophyseal System physiology
Photoperiod
Pituitary-Adrenal System physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0013-7227
- Volume :
- 148
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Endocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 17395702
- Full Text :
- https://doi.org/10.1210/en.2006-1432