Different studies have elucidated the mechanisms underlying the formation and expression of drug-related cue memories; corticotrophin-releasing factor (CRF) plays a critical role in reward- and aversion-driven associative learning. In the present chapter, we have evaluated whether CP-154,526, a selective CRF1 receptor (CRF1R) antagonist, or genetic deletion of CRF1R (KO mice) have comparable effects on conditioned place preference (CPP) and conditioned place aversion (CPA) learning. We also investigated CP-154,526 effects on morphine-induced CPP activation of CRF, CREB phosphorylation, and thioredoxin (Trx1) expression in dentate gyrus (DG), a brain region involved in memory consolidation, and the role of hypothalamic-pituitary-adrenocortical (HPA) axis in CPA expression and extinction. The CRF1R antagonist abolished the acquisition of morphine CPP, Trx-1 and BDNF increased expression, and pCREB/Trx-1 co-localization in the DG. The increase in adrenocorticotropic hormone (ACTH) plasma levels observed after CPA expression was attenuated in CRF1R KO mice, suggesting a role of HPA axis in aversive memories. Altogether, these results suggest a critical role of CRF, through CRF1R, in molecular changes involved in memory formation and consolidation and may facilitate the development of effective treatments for opioid addiction.
Part of the book: Opioids