Chronic unpredictable stress causes attenuation of serotonin responses in cornu ammonis 1 pyramidal neurons

E Van Riel*, OC Meijer, PJ Steenbergen, M Joels

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

57 Citations (Scopus)

Abstract

In the present study, serotonin (5-HT) responses of hippocampal pyramidal cornu ammonis 1 (CAI) neurons were studied in rats subjected twice daily for 21 days to unpredictable stressors. In hippocampal tissue from thus stressed rats mRNA expression of the 5-HT1A receptor and mineralo- as well as glucocorticoid receptors were examined with in situ hybridization. On average, stressed rats displayed increased adrenal weight and attenuated body weight gain compared with controls, supporting that the animals had experienced increased corticosterone levels due to the stress exposure. One day after the last stressor, under conditions that corticosterone levels were low (predominant mineralocorticoid receptor activation), the 5-HT1A receptor mediated hyperpolarization of CA1 neurons in response to 10 muM 5-HT was significantly reduced compared with controls. Basal membrane properties of CA1 cells in stressed rats were comparable to those of controls. The 5-HT1A receptor mRNA expression was not changed after chronic stress exposure, in any of the hippocampal areas. A small but significant increase in mineralocorticoid receptor mRNA expression was observed after stress in the dentate gyrus, while glucocorticoid receptor expression was unchanged. The data indicate that unpredictable stress exposure for 3 weeks results in suppression of 5-HT1A receptor-mediated responses, possibly due to posttranslational modification of the receptor. (C) 2003 IBRO. Published by Elsevier Science Ltd. All rights reserved. Key

Original languageEnglish
Pages (from-to)649-658
Number of pages10
JournalNeuroscience
Volume120
Issue number3
DOIs
Publication statusPublished - Sep-2003
Externally publishedYes

Keywords

  • corticosterone
  • mineralocorticoid receptor
  • glucocorticoid receptor
  • serotonin-1A receptor
  • electrophysiology
  • in situ hybridization
  • HIPPOCAMPAL CA1 NEURONS
  • RECEPTOR GENE-TRANSCRIPTION
  • II CORTICOSTEROID RECEPTORS
  • MESSENGER-RNA EXPRESSION
  • RAT HIPPOCAMPUS
  • IN-VIVO
  • POTASSIUM CURRENT
  • 5-HT1A
  • BRAIN
  • DEPRESSION

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