title: Morphine differentially regulates hsp90beta expression in the nucleus accumbens of Lewis and Fischer 344 rats.
abstract: We have comparatively studied hsp90beta gene and protein expression in the nucleus accumbens of Lewis and Fischer 344 (F344) rats, two inbred strains that exhibit prominent behavioural differences in drug-seeking behaviours. Phenotypical studies confirmed that Lewis rats developed a higher preference for morphine-paired environments after conditioning. RT-PCR assays did not reveal strain-related differences in hsp90beta gene expression in basal conditions; however, acute morphine treatment provoked an increase of hsp90beta mRNA 2h after injection only in the case of Lewis rats. We also found a significant upregulation of the Hsp90beta protein in both strains 8h after morphine injection, this increase being significantly higher in Lewis rats. Taking into account the suggested roles for Hsp90 in the brain, the data suggest that Lewis and F344 strain differences concerning opioid-seeking behaviours could be related to differential sensitivity to opioid-induced neuronal plasticity within the brain reward system, an effect that could be mediated (at least partially) by stress proteins.
authors.affiliation: Departamento de Farmacología, Tecnología y Desarrollo Farmacéutico, Univ. San Pablo CEU, Spain.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Salas
authors.forename: Elba
authors.initials: E
authors.lastname: Alonso
authors.forename: Julio
authors.initials: J
authors.lastname: Sevillano
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Herradon
authors.forename: Carlos
authors.initials: C
authors.lastname: Bocos
authors.forename: Lidia
authors.initials: L
authors.lastname: Morales
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Ramos
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: Alguacil
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010641:Phenotype; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew
chemical_list: D000701:Analgesics, Opioid; D018841:HSP90 Heat-Shock Proteins; D009020:Morphine