Monoamines in the dorsomedial hypothalamus of rats following exposure to different tests of 'anxiety'

Tammy J. Sajdyk, Jason S. Katner, Anantha Shekhar

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Adult male Sprague-Dawley rats were subjected to the fear-potentiated startle, elevated plus-maze and social interaction tests and the levels of norepinephrine, dopamine and serotonin in the dorsomedial hypothalamus were determined by high-performance liquid chromatography. Only rats subjected to the full fear potentiated startle test and not the other tests of anxiety or components (foot shocks or acoustic startle) of fear-potentiated startle showed significant increases in norepinephrine and dopamine levels after 24 hours. A time course experiment specific for the norepinephrine changes in the dorsomedial hypothalamus of fear-potentiated startle rats revealed a significant increase in tissue content as compared to controls at both the 12 and 24 hour post-test time points. Tyrosine hydroxylase activity in the dorsomedial hypothalamus of the fear-potentiated startle rats did not show a significant change from controls. An in vitro release study found a significant decrease in potassium-stimulated release of norepinephrine in the dorsomedial hypothalamus as compared to controls at 24 hours post-test. These results suggest that animals exposed to fear-potentiated startle and not other tests of 'anxiety' have a change in tissue catecholamine levels and that the norepinephrine change may be the result of a decrease in release and not an increase in synthesis.

Original languageEnglish (US)
Pages (from-to)193-209
Number of pages17
JournalProgress in Neuro-Psychopharmacology and Biological Psychiatry
Volume21
Issue number1
DOIs
StatePublished - Jan 1 1997

Keywords

  • dopamine
  • elevated plus maze
  • fear-potentiated startle
  • norepinephrine
  • serotonin
  • social interaction
  • stress
  • tyrosine hydroxylase

ASJC Scopus subject areas

  • Biological Psychiatry
  • Pharmacology

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