Regulation of nitric oxide synthase messenger RNA expression in the rat hippocampus by glucocorticoids

M. O. López-Figueroa, K. Itoi, S. J. Watson

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Nitric oxide and glucocorticoids have been implicated in learning and memory, as well as in regulation of the stress response. By use of the in situ hybridization technique, we examined the role of glucocorticoids in the regulation of nitric oxide synthase messenger RNA in the hippocampus. In control animals, nitric oxide synthase subtype I (neuronal) messenger RNA was expressed in the CA1, CA3 and dentate gyrus of the hippocampus. Nitric oxide synthase subtype I expression was almost absent in CA2 pyramidal neurons. Neither subtype II (immunological) nor subtype III (endothelial) nitric oxide synthase messenger RNAs were observed in neurons of the hippocampal subfields. Bilateral removal of the adrenal glands resulted in a significant increase in nitric oxide synthase subtype I messenger RNA expression in the CA1 and CA3 pyramidal neurons and in granular cells of the dentate gyrus. To a lesser degree, the nitric oxide synthase subtype I messenger RNA signal was increased in CA2 pyramidal neurons. Daily administration of glucocorticoids for one week attenuated the adrenalectomy-induced increased level of expression of the messenger RNA encoding nitric oxide synthase subtype I in all areas studied. Because adrenalectomy, which suppresses the production of glucocorticoids, increases nitric oxide synthase expression, and replacement of adrenalectomized animals with glucocorticoids restores the basal levels of nitric oxide synthase subtype I expression, our results demonstrate an up- regulation of nitric oxide synthase subtype I messenger RNA in the absence of glucocorticoids in the hippocampus. The present findings suggest an involvement of the stress axis in the regulation of the synaptic plasticity process mediated by nitric oxide in the hippocampus.

Original languageEnglish
Pages (from-to)439-446
Number of pages8
JournalNeuroscience
Volume87
Issue number2
DOIs
Publication statusPublished - 1998 Jul 20

Keywords

  • Adrenalectomy
  • Hippocampus
  • In situ hybridization
  • Nitric oxide synthase
  • Pyramidal neurons
  • Steroids

ASJC Scopus subject areas

  • Neuroscience(all)

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