Present address: School of Health & Social Care, University College Chester, Parkgate Road, Chester CH1 4BJ, UK.
Regulation of corticosteroid receptors in the rat brain: the role of serotonin and stress
Version of Record online: 8 APR 2005
European Journal of Neuroscience
Volume 21, Issue 6, pages 1511–1520, March 2005
How to Cite
Robertson, D. A. F., Beattie, J. E., Reid, I. C. and Balfour, D. J. K. (2005), Regulation of corticosteroid receptors in the rat brain: the role of serotonin and stress. European Journal of Neuroscience, 21: 1511–1520. doi: 10.1111/j.1460-9568.2005.03990.x
- Issue online: 12 APR 2005
- Version of Record online: 8 APR 2005
- Received 4 May 2004, revised 30 December 2004, accepted 10 January 2005
It has been suggested that physiological resistance to repeated stress is associated with increased 5-hydroxytryptamine (5-HT) release in the dorsal hippocampus and that dysregulation of this neuroadaptation may be implicated in the psychopathology of depression. This study used 5,7-dihydroxytryptamine lesions to investigate the role of 5-HT projections to the hippocampus in physiological responses to repeated stress and putative changes in corticosteroid receptor immunoreactivity in the brain. Repeated exposure to elevated open platform stress (1 h/day) caused regionally selective changes in glucocorticoid and mineralocorticoid receptor immunoreactivity in the dorsal hippocampus that were not observed in ventral hippocampus, frontal cortex, hypothalamus or parietal cortex. Glucocorticoid receptor immunoreactivity in the dorsal hippocampus was decreased after 5 days but increased after 20 days of stress. Mineralocorticoid receptor immunoreactivity was increased after 5 or 10 days of stress. The increases in glucocorticoid and mineralocorticoid receptor immunoreactivity, evoked by repeated stress, were abolished by lesions of the principal 5-HT projections to the hippocampus. The lesions abolished the increased defecation observed in stressed animals, but had no effects on the plasma corticosterone response to the stressor or the habituation of this response observed following repeated stress. The experiments have revealed a dissociation in the regulation of corticosteroid receptor expression in the dorsal and ventral hippocampus by repeated stress and 5-HT. The data suggest that adaptation to inescapable stress is associated with regionally selective changes in corticosteroid receptor expression in dorsal hippocampus that are largely 5-HT-dependent, although these changes do not mediate habituation of the pituitary adrenocortical response to the stressor.