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

Demitri F. Papolos, Emmeline Edwards, Ronen Marmur, Herbert M. Lachman, Fritz A. Henn

Research output: Contribution to journalArticle

36 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)304-309
Number of pages6
JournalBrain Research
Volume615
Issue number2
DOIs
StatePublished - Jul 2 1993

Keywords

  • Antiglucocorticoid
  • Dentate gyrus
  • Learned helplessness
  • RU 38486

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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