title: Protective effects of atorvastatin against morphine-induced tolerance and dependence in mice.
abstract: In this study, we evaluated the effects of atorvastatin, a lipid-lowering medication on morphine-induced tolerance and dependence in mice.
  
  
  
  Tolerance was induced by subcutaneous administration of morphine (20mg/kg) to animals, twice a day for 9days. Atorvastatin was given at the doses of 5, 10 and 20mg/kg, 30min before each morphine administration, once daily for 9days. Hot plate test was employed to assess antinociceptive effect of morphine on days 1, 3, 5, 7 and 9. Dependence was evaluated by naloxone-precipitated withdrawal syndrome. We attempted to verify withdrawal regulation of induced nitric oxide synthase (iNOS), astroglia marker, glial fibrillary acidic protein (GFAP), ionized calcium-binding protein (Iba1), a microglia activation marker, a pro-inflammatory mediator, tumor necrosis alpha (TNF-α) and immune receptor, toll like receptor 4 (TLR-4) genes by real-time polymerase chain reaction (RT-PCR). Lipid peroxidation was estimated by assessing malondialdehyde (MDA) content in the spinal cord of animals.
  
  
  
  Tolerance to antinociceptive effects of morphine was observed on days 7 and 9. Decrease in morphine-induced antinociception was reversed by concomitant intraperitoneal administration of atorvastatin (10 and 20mg/kg). Atorvastatin (10 and 20mg/kg) mitigated naloxone-induced withdrawal parameters. Brain expression levels of TNF-α, GFAP, Iba1 and iNOS increased in morphine withdrawn animals which were attenuated by nine days treatment with atorvastatin. Increased MDA was also normalized in withdrawn animals received atorvastatin.
  
  
  
  Atorvastatin exhibits meaningful protective effects against both tolerance to antinociceptive effects of morphine and withdrawal-induced behavioral profile. Neuroprotective effects of atorvastatin is further supported via inhibition of glia activity and antioxidant effects.
authors.affiliation: Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Nasim Sadat
authors.initials: NS
authors.lastname: Pajohanfar
authors.affiliation: Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Mohebbi
authors.affiliation: Cellular and Molecular Research Center, Department of Biochemistry and Nutrition, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Rad
authors.affiliation: Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Pejhan
authors.affiliation: Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran.
authors.forename: Samad
authors.initials: S
authors.lastname: Nazemi
authors.affiliation: Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran. Electronic address: aminb@medsab.ac.ir.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Amin
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D000069059:Atorvastatin / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004361:Drug Tolerance / Q000502:physiology; D008297:Male; D051379:Mice; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000188:drug therapy* / Q000378:metabolism; D009270:Naloxone / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D059225:Nociception / Q000187:drug effects / Q000502:physiology; D011897:Random Allocation; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy / Q000378:metabolism
chemical_list: D000975:Antioxidants; D009294:Narcotics; D009270:Naloxone; D009020:Morphine; D000069059:Atorvastatin
keywords: Antioxidant; Glia; Morphine tolerance; Morphine withdrawal; Statins