title: Verifying of participation of nitric oxide in morphine place conditioning in the rat medial septum using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d).
abstract: BACKGROUND
  Role of nitric oxide (NO) in morphine-induced conditioned place preference (CPP) has already been proposed in the rat medial septum (MS), but no molecular evidence has been provided to clear this fact.
  
  
  METHODS
  Effects of intraseptal injections of L-arginine and/or NG-nitro-L-arginine methyl ester (L-NAME) on morphine place conditioning in Wistar rats were examined. Morphine (2.5-7.5 mg/kg) was injected s.c. using a three-day schedule of an unbiased place preference. All of the brain samples were examined histochemically by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d), the main marker for NO activation.
  
  
  RESULTS
  Morphine induced a significant CPP in the rats. Single injections of L-arginine or L-NAME (0.3, 1.0 and 3.0 µg/rat) did not induce CPP. In addition, co-administration of morphine (5.0 mg/kg) with L-arginine or L-NAME (0.3, 1.0 and 3.0 µg/rat) did not affect morphine response. However, administration of L-arginine (0.3, 1.0 and 3.0 µg/rat) prior to morphine conditioning testing enhanced the expression of morphine response. Moreover, pre-injection of L-NAME (0.3, 1.0 and 3.0 µg/rat) to L-arginine (0.3 µg/rat) did not reverse the response to the agent. The expression of NADPH-d was observed in the rat brain samples treated by L-arginine. A decreased expression of NADPH-d was also observed in rats pre-injected by L-NAME.
  
  
  CONCLUSIONS
  This finding strongly suggests that NO system in the rat MS has an impact on the expression of morphine rewarding, and that the NO participates in place conditioning induced of morphine.
authors.affiliation: Dept. of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran. karami@shahed.ac.ir
authors.forename: Manizheh
authors.initials: M
authors.lastname: Karami
authors.forename: Mohsen
authors.initials: M
authors.lastname: Karimian Azimi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Khalaji
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology; D002755:Choice Behavior / Q000187:drug effects* / Q000502:physiology*; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D006651:Histocytochemistry; D007267:Injections; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009249:NADP / Q000032:analysis; D009252:NADPH Dehydrogenase / Q000096:biosynthesis*; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020665:Septum of Brain / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*
chemical_list: D000701:Analgesics, Opioid; D009569:Nitric Oxide; D009249:NADP; D009020:Morphine; D001120:Arginine; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase; D019331:NG-Nitroarginine Methyl Ester