Effects of acidic-astressin and ovine-CRF microinfusions into the ventral hippocampus on defensive behaviors in rats.
This study investigated a possible role for ventral hippocampal corticotropin-releasing factor (CRF) in modulating both unconditioned and conditioned defensive behaviors by examining the effects of pre-training ventral hippocampal ovine-CRF (oCRF) or acidic-astressin ([Glu(11,16)]Ast) microinfusions in male Long-Evans hooded rats exposed to various threat stimuli including the elevated plus-maze (EPM) (oCRF), cat odor (oCRF and [Glu(11,16)]Ast) and a live cat ([Glu(11,16)]Ast). Unconditioned defensive behaviors were assessed during threat exposure, while conditioned defensive behaviors were assessed in each predator context 24 h after the initial threat encounter. Pre-training infusions of the CRF(1) and CRF(2) receptor agonist oCRF significantly increased defensive behaviors during both the unconditioned and conditioned components of the cat odor test, as well as exposure to the EPM. In contrast to the behavioral effects of oCRF microinfusions, the CRF(1) and CRF(2) receptor antagonist [Glu(11,16)]Ast significantly decreased defensive behaviors during exposure to cat odor, while producing no discernible effects following a second injection in the cat exposure test. During conditioned test trials, pre-training infusions of [Glu(11,16)]Ast also significantly reduced defensive behaviors during re-exposure to both predator contexts. These results suggest a specific role for ventral hippocampal CRF receptors in modulating anxiety-like behaviors in several ethologically relevant animal models of defense.
Pentkowski
Nathan S
NS
Department of Psychology, University of Hawaii, Honolulu, Hawaii 96822, USA. pentkows@hawaii.edu
Litvin
Yoav
Y
Blanchard
D Caroline
DC
Vasconcellos
Amy
A
King
Lanikea B
LB
Blanchard
Robert J
RJ
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D002404:Catheterization; D002415:Cats; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D009812:Odorants; D010446:Peptide Fragments / Q000008:administration & dosage; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D018019:Receptors, Corticotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D010446:Peptide Fragments; D018019:Receptors, Corticotropin-Releasing Hormone; C104416:astressin; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone