title: Facilitating influence of stress on the consolidation of fear memory induced by a weak training: reversal by midazolam pretreatment.
abstract: It is well known that an emotionally arousing experience usually results in a robust and persistent memory trace. The present study explored the potential mechanisms involved in the influence of stress on the consolidation of a contextual fear memory in animals subjected to a weak fear training protocol, and whether pretreatment with intra-basolateral amygdala or systemic administration of midazolam (MDZ) prevents the potential stress-induced influence on fear memory formation. A previous restraint session facilitated fear retention, this effect was not due to a sensitized effect of restraint on the footshock experience. MDZ, both systemically or intra-basolateral amygdala infusion prior to the restraint, attenuated the stress-induced promoting influence on fear memory formation. In addition, stress exposure activated the ERK1/2 pathway in basolateral amygdala (BLA) after the weak training procedure but not after the immediate footshock protocol. Similar to our behavioral findings, MDZ attenuated stress-induced elevation of phospho-ERK2 (p-ERK2) in BLA following the acquisition session. Given that the activation of ERK1/2 pathway is essential for associative learning, we propose that stress-induced facilitation of p-ERK2 in BLA is an important mechanism for the promoting influence of stress on the consolidation of contextual fear memory.
authors.affiliation: IFEC-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina. nmaldonado@fcq.unc.edu.ar
authors.forename: Noelia Martina
authors.initials: NM
authors.lastname: Maldonado
authors.forename: Irene Delia
authors.initials: ID
authors.lastname: Martijena
authors.forename: Víctor Alejandro
authors.initials: VA
authors.lastname: Molina
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004597:Electroshock / Q000379:methods; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects*; D008874:Midazolam / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D018686:Anesthetics, Intravenous; D048049:Extracellular Signal-Regulated MAP Kinases; D008874:Midazolam