title: Reversal effect of intra-central amygdala microinjection of L-arginine on place aversion induced by naloxone in morphine conditioned rats.
abstract: Role of nitric oxide (NO) on expression of morphine conditioning using a solely classic task has been proposed previously. In this work, the involvement of NO on the expression of opioid-induced conditioning in the task paired with an injection of naloxone was investigated.
  
  
  
  Conditioning was established in adult male Wistar rats (weighing 200-250 g) using an unbiased procedure. Naloxone (0.05-0.4 mg/kg, i.p.), a selective antagonist of mu-opioid receptor, was administered once prior to morphine response testing. NO agents were administered directly into the central amygdala (CeA) prior to naloxone injection pre-testing.
  
  
  
  Morphine (2.5-10 mg/kg, s.c.) produced a significant dose-dependent place preference in experimental animals. When naloxone (0.05-0.4 mg/kg, i.p.) was injected before testing of morphine (5 mg/kg, s.c.) response, the antagonist induced a significant aversion. This response was reversed due to injection of L-arginine (0.3-3 microg/rat), intra-CeA prior to naloxone administration. However, pre-injection of L-NAME (intra-CeA), an inhibitor of NO production, blocked this effect.
  
  
  
  The finding may reflect that NO in the nucleus participates in morphine plus naloxone interaction.
authors: Dept. of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
authors: Sara
authors: S
authors: Karimi
authors: Dept. of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
authors: Manizheh
authors: M
authors: Karami
authors: Dept. of Physiology and Biophysics, 
  Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors: Hedayat
authors: H
authors: Sahraei
authors: Dept. of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran.
authors: Mahnaz
authors: M
authors: Rahimpour
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology; D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D003216:Conditioning, Operant; D004305:Dose-Response Relationship, Drug; D008297:Male; D008845:Microinjections; D009020:Morphine / Q000008:administration & dosage*; D009270:Naloxone / Q000008:administration & dosage*; D009292:Narcotic Antagonists / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009292:Narcotic Antagonists; D009270:Naloxone; D009020:Morphine; D001120:Arginine