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CRF1 and CRF2 receptors are required for potentiated startle to contextual but not discrete cues.
Neuropsychopharmacology 34, 1494-1503 (2009)
Corticotropin-releasing factor (CRF) peptides and their receptors have crucial roles in behavioral and endocrine responses to stress. Dysregulation of CRF signaling has been linked to post-traumatic stress disorder, which is associated with increased startle reactivity in response to threat. Thus, understanding the mechanisms underlying CRF regulation of startle may identify pathways involved in this disorder. Here, we tested the hypothesis that both CRF1 and CRF2 receptors contribute to fear-induced increases in startle. Startle responses of wild type (WT) and mice with null mutations (knockout, KO) for CRF1 or CRF2 receptor genes were measured immediately after footshock (shock sensitization) or in the presence of cues previously associated with footshock (ie fear-potentiated startle, FPS). WT mice exhibited robust increases in startle immediately after footshock, which was dependent upon contextual cues. This effect was completely absent in CRF1 KO mice, and significantly attenuated in CRF2 KO mice. In contrast, CRF1 and CRF2 KO mice exhibited normal potentiation of startle by discrete conditioned cues. Blockade of both receptors via CRF1 receptor antagonist treatment in CRF2 KO mice also had no effect on FPS. These results support an additive model of CRF1 and CRF2 receptor activation effects on potentiated startle. These data also indicate that both CRF receptor subtypes contribute to contextual fear but are not required for discrete cued fear effects on startle reactivity. Thus, we suggest that either CRF1 or CRF2 could contribute to the increased startle observed in anxiety disorders with CRF system abnormalities.
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Publication type
Article: Journal article
Document type
Scientific Article
Keywords
CRF; startle; conditioned fear; PTSD; fear potentiated startle; context fear
ISSN (print) / ISBN
0893-133X
e-ISSN
1470-634X
Journal
Neuropsychopharmacology
Quellenangaben
Volume: 34,
Issue: 6,
Pages: 1494-1503
Publisher
Nature Publishing Group
Non-patent literature
Publications
Reviewing status
Peer reviewed
Institute(s)
CCG Molecular Neurogenetics (IDG-KMN)