Effects of CORT pretreatment on basal and stress-induced PVN cfos mRNA levels of non-CX or CX pretreated rats. (A,B) In the absence of CX pretreatment, restraint induced PVN c-fos mRNA, and neither 1 h or 3 h CORT pretreatment suppressed that induction. (C,D) Systemic pretreatment with CX increased PVN c-fos mRNA levels in all groups, irrespective of acute stress or CORT treatment condition. Panels B and D show representative autoradiographic images of the bilateral PVN portion of coronal brain sections from key comparison conditions depicted in panels A and C, respectively. Values are presented as a percentage of the mean value of the non-CX pretreated stressed 3 h vehicle rats. *, represents a significant stress effect within same drug condition and pretreatment time point (p < 0.05, FLSD); R, represents a significant difference between CX pretreated rats (C) compared to the corresponding non-CX treated rats (A) (p < 0.05, FLSD).