title: Effect of environmental enrichment on physical and psychological dependence signs and voluntary morphine consumption in morphine-dependent and morphine-withdrawn rats.
abstract: This study was designed to examine the effect of environmental enrichment during morphine dependency and withdrawal on the severity of naloxone-precipitated withdrawal signs, anxiety, and depressive-like behaviors and voluntary morphine consumption in morphine-dependent rats. The rats were injected with bi-daily doses (10 mg/kg, 12 h intervals) of morphine for 14 days following rearing in a standard environment (SE) or enriched environment (EE) during the development of morphine dependence and withdrawal. Then, rats were tested for withdrawal signs after naloxone injection, anxiety (the elevated plus maze) and depression-related behavior (sucrose preference test), and voluntary consumption of morphine using a two-bottle choice paradigm, in morphine-dependent and morphine-withdrawn rats. The results showed that EE decreased naloxone-precipitated withdrawal signs, but not anxiety or sucrose preference during dependence on morphine. The EE-withdrawn rats showed an increase in the elevated plus maze open arm time and entries and higher levels of sucrose preference than SE rats. Voluntary consumption of morphine was lower in the EE-withdrawn rats than in the SE groups in the second period of drug intake. Thus, exposure to EE reduced the severity of morphine dependence and voluntary consumption of morphine, alongside reductions in anxiety and depression-related behavior in morphine-withdrawn rats.
authors.affiliation: aFaculty of Psychology and Educational Sciences, University of Semnan bLaboratory of Animal Addiction Models, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan cFaculty of Educational Sciences and Psychology, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: Arezoo
authors.initials: A
authors.lastname: Hammami-Abrand Abadi
authors.forename: Hossein
authors.initials: H
authors.lastname: Miladi-Gorji
authors.forename: Imanollah
authors.initials: I
authors.lastname: Bigdeli
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000209:etiology; D002755:Choice Behavior / Q000187:drug effects; D004195:Disease Models, Animal; D004777:Environment; D005518:Food Preferences / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D009020:Morphine / Q000008:administration & dosage; D009021:Morphine Dependence / Q000503:physiopathology / Q000523:psychology* / Q000628:therapy*; D009270:Naloxone / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000627:therapeutic use; D009294:Narcotics / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology / Q000523:psychology / Q000628:therapy
chemical_list: D009292:Narcotic Antagonists; D009294:Narcotics; D009270:Naloxone; D009020:Morphine