Blockade of CCKB but not CCKA receptors before and after the stress of predator exposure prevents lasting increases in anxiety-like behavior: Implications for anxiety associated with posttraumatic stress disorder.
Lasting increases in anxiety-like behavior (ALB) in rodents in the elevated plus maze have been reported to follow brief (5 min) exposures to a cat. This study examined the role of CCK A and CCK B receptors in lasting increases in ALB following exposure to a cat. Block of CCK B receptors 30 min before and after cat exposure prevented increases in ALB assessed I week later in the elevated plus maze. Blocks of CCK A receptors either before or after cat exposure were without effect on increases in ALB measured I week later. Changes in activity or exploration could not account for the results. Effects of cat exposure on ALB, startle, and corticosteroid levels have been proposed as a model of affective disorder in posttraumatic stress disorder (PTSD). Implications of these findings for mechanisms of initiation of anxiety in PTSD and posttrauma pharmacological prophylaxis in PTSD are discussed.