title: Subsequently enhanced CPP to morphine following chronic but not acute footshock stress associated with corticosterone mechanism in rats.
abstract: The purpose of this study was to determine the morphine-induced place preference in rats pre-exposed to footshock stress and corticosterone (CORT). The authors also studied the involvement of dopamine mechanisms in the CORT-induced place preference. The results showed that chronic footshock or CORT exposure but not acute footshock or CORT exposure similarly potentiated the conditioned place preference to morphine. The CORT-induced conditioned place preference were established only with high and middle dose (5, 3 mg/kg) CORT. The dopamine levels in NAc of rats injected with CORT (5, 3, 1 mg/kg, i.p.) increased significantly. The findings suggest that the increase of dopamine levels in NAc induced by CORT might be the medium between stress and morphine.
authors.affiliation: Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha Hunan, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Gong-Ying
authors.initials: GY
authors.lastname: Li
authors.forename: Ling-Jiang
authors.initials: LJ
authors.lastname: Li
authors.forename: Chong-Hong
authors.initials: CH
authors.lastname: Wang
authors.forename: Ze-Xuan
authors.initials: ZX
authors.lastname: Li
authors.forename: Jin-Li
authors.initials: JL
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Wei-Hui
authors.initials: WH
authors.lastname: Li
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects*; D003345:Corticosterone / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004597:Electroshock / Q000009:adverse effects*; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D009294:Narcotics / Q000008:administration & dosage*; D009714:Nucleus Accumbens / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D013997:Time Factors
chemical_list: D009294:Narcotics; D009020:Morphine; D004298:Dopamine; D003345:Corticosterone