Paradoxical hormonal and behavioral responses to hypothyroid and hyperthyroid states in the Wistar-Kyoto rat

Eva E. Redei*, Leah C. Solberg, Joseph M. Kluczynski, William P. Pare

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Wistar-Kyoto (WKY) rats show endogenous depressive behavior that can be reversed by antidepressants. Given that WKYs exhibit decreased sensitivity to some antidepressants and treatment-resistant depressed patients often show hypothalamic-pituitary-thyroid (HPT) dysregulation, we examined the behavioral and HPT hormonal responses of WKYs to altered thyroid status. "Euthyroid" WKYs had elevated basal plasma TSH and T3 levels as compared to Wistars. Hypothyroidism increased TSH levels more in WKYs than in Wistars and increased response latency in the open field test (OFT) of WKYs only. Administration of T4 and T3 suppressed plasma TSH equally in both strains. Wistars responded to increased T3 levels with decreased response latency and increased activity in the OFT, but increased immobility in the forced swim test. In contrast, WKYs responded only to the high T3 levels with decreased response latency in the OFT. These results suggest the existence of a decreased central nervous system sensitivity to thyroid hormones in WKYs that could be related to their depressive behavior.

Original languageEnglish (US)
Pages (from-to)632-639
Number of pages8
JournalNeuropsychopharmacology
Volume24
Issue number6
DOIs
StatePublished - Jun 2001

Keywords

  • Depression model
  • Forced swim test
  • Open field test
  • Strains
  • T

ASJC Scopus subject areas

  • Pharmacology
  • Psychiatry and Mental health

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