Effects of the antiglucocorticoid RU 38486 on the induction of learned helpless behavior in Sprague-Dawley rats

Papolos, D. F., Edwards, E., Marmur, R., Lachman, H. M., Henn, F. A. (July 1993) Effects of the antiglucocorticoid RU 38486 on the induction of learned helpless behavior in Sprague-Dawley rats. Brain Research, 615 (2). pp. 304-9. ISSN 0006-8993 (Print)0006-8993 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/8364739
DOI: 10.1016/0006-8993(93)90042-L

Abstract

Learned helplessness (LH) is induced by exposure to an inescapable or uncontrollable stressor which results in an inability to escape or avoid the same stressor when subsequently presented in a different context. In order to understand which central mechanisms may influence the expression of the learned helpless phenotype, we have pursued an experimental approach that seeks to elucidate the behavioral effects of glucocorticoid (GC) hormones in this animal model of depression. We have previously shown that the induction of LH behavior is enhanced by adrenalectomy, an effect that is reversed by corticosterone. In this study, our aim was to attempt to locate CNS sites responsible for the observed effects of glucocorticoids on learned helpless behavior by introducing the type II GC receptor antagonist, RU 38486 to discrete brain regions. We did not observe a significant effect in LH with acute systemic, acute dentate gyrus or intracerebroventricular injection of RU 38486 in contrast to previous studies using the Porsolt swim test, another animal model of depression. However, we were able to observe a significant change upon chronic administration to the dentate gyrus. These findings suggest that glucocorticoids exert a long-term influence on stress-induced behavior, presumably by affecting glucocorticoid responsive genes in the dentate gyrus.

Item Type: Paper
Uncontrolled Keywords: Animals Glucocorticoids/*antagonists & inhibitors *Helplessness, Learned Hippocampus/physiology Injections Injections, Intraventricular Injections, Subcutaneous Mifepristone/*pharmacology Rats Rats, Sprague-Dawley Time Factors
Subjects: diseases & disorders > mental disorders > mood disorders > depression
organism description > animal > mammal > rodent > rat
organism description > animal > mammal > rodent > rat
CSHL Authors:
Communities: CSHL labs > Henn lab
Depositing User: Matt Covey
Date: 2 July 1993
Date Deposited: 06 Jun 2014 20:33
Last Modified: 06 Jun 2014 20:33
Related URLs:
URI: http://repository.cshl.edu/id/eprint/30245

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