Regulation of fear responses by striatal and extrastriatal adenosine A2Areceptors in forebrain

Catherine J. Wei, Elisabete Augusto, Catarina A. Gomes, Philipp Singer, Yumei Wang, Detlev Boison, Rodrigo A. Cunha, Kay Yan Benjamin Yee, Jiang Fan Chen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

54 Citations (Scopus)

Abstract

Background Adenosine A2Areceptors (A2ARs) are enriched in the striatum but are also present at lower levels in the extrastriatal forebrain (i.e., hippocampus, cortex), integrating dopamine, glutamate, and brain-derived neurotrophic factor (BDNF) signaling, and are thus essential for striatal neuroplasticity and fear and anxiety behavior. Methods We tested two brain region-specific A2AR knockout lines with A2ARs selectively deleted either in the striatum (st-A2AR KO) or the entire forebrain (striatum, hippocampus, and cortex [fb-A2AR KO]) on fear and anxiety-related responses. We also examined the effect of hippocampus-specific A2AR deletion by local injection of adeno-associated virus type 5 (AAV5)-Cre into floxed-A2AR knockout mice. Results Selectively deleting A2ARs in the striatum increased Pavlovian fear conditioning (both context and tone) in st-A2AR KO mice, but extending the deletion to the rest of the forebrain apparently spared context fear conditioning and attenuated tone fear conditioning in fb-A2AR KO mice. Moreover, focal deletion of hippocampal A2ARs by AAV5-Cre injection selectively attenuated context (but not tone) fear conditioning. Deletion of A2ARs in the entire forebrain in fb-A2AR KO mice also produced an anxiolytic phenotype in both the elevated plus maze and open field tests, and increased the startle response. These extrastriatal forebrain A2AR behavioral effects were associated with reduced BDNF levels in the fb-A2AR KO hippocampus. Conclusions This study provides evidence that inactivation of striatal A2ARs facilitates Pavlovian fear conditioning, while inactivation of extrastriatal A2ARs in the forebrain inhibits fear conditioning and also affects anxiety-related behavior.
Original languageEnglish
Pages (from-to)855-863
Number of pages9
JournalBiological Psychiatry
Volume75
Issue number11
DOIs
Publication statusPublished - 1 Jun 2014
Externally publishedYes

Keywords

  • anxiety
  • BDNF
  • cortex
  • fear conditioning
  • hippocampus
  • startle response
  • striatum

ASJC Scopus subject areas

  • Biological Psychiatry

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