Effects of acute and repeated restraint stress on corticotropin-releasing hormone binding protein mRNA in rat amygdala and dorsal hippocampus

Corticotropin-releasing hormone (CRH) mediates endocrine, behavioral, and a utonomic responses to stress. In addition to binding to two receptor subtyp es, CRH binds to a CRH-binding protein (CRH-BP). While CRH-BP is hypothesiz ed to play a role in regulating levels of free CRH and modulating the stres s response, the effects of stressors on brain CRH-BP are relatively unexplo red. The present study determined effects of acute and repeated restraint o n CRH-BP mRNA in basolateral amygdala (BLA) and dorsal hippocampus (DH), br ain regions involved in fear and motivation. Using in situ hybridization, w e found that a single acute period of restraint significantly increased CRH -BP mRNA in BLA by 20% but had no effect in DH. Repeated restraint had no e ffect on basal levels of CRH-BP mRNA in BLA or DH. importantly, repeated re straint blocked the effects of acute restraint in the BLA. These results de monstrate differential effects of acute and repeated restraint on CRH-BP mR NA. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.