The CCK2 agonist BC264 reverses freezing behavior habituation in PVG hooded rats on repeated exposures to a cat.
Our previous studies (NeuroReport 12 (2001) 2717) showed that PVG hooded and not Sprague-Dawley (SD) rats exhibit remarkable freezing behavior on exposure to a cat in the cat freezing test apparatus. In the present study, we further examined the differences between these two strains of rats in response to repeated daily exposure to a cat in the cat freezing test apparatus. Freezing behavior habituation was observed in both PVG hooded (days 5-7) and SD rats (days 3-7). A selective CCK(2) agonist (BC264, 0.3 microg/kg, i.p.) on day 8 reversed habituated freezing behavior and locomotor activity in PVG hooded rats, but not in SD rats. These results suggest that CCK2 receptors mediate habituation to an anxiety-inducing stimulus in PVG hooded rats and further suggest that differential expression of these CCK2 receptors underlies this strain difference.
Farook
J M
JM
Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA. farook@uthscsa.edu
McLachlan
C S
CS
Zhu
Y Z
YZ
Lee
L
L
Moochhala
S M
SM
Wong
P T-H
PT
D000818:Animals; D002415:Cats; D002766:Cholecystokinin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006185:Habituation, Psychophysiologic / Q000187:drug effects* / Q000502:physiology; D007103:Immobilization / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043887:Receptor, Cholecystokinin B / Q000819:agonists* / Q000502:physiology; D013045:Species Specificity
C084553:BC 264; D010446:Peptide Fragments; D043887:Receptor, Cholecystokinin B; D002766:Cholecystokinin