title: GABA(A) receptors in the basolateral amygdala are involved in mediating morphine reward.
abstract: In the present study, the effects of intra-basolateral amygdala (BLA) injection of GABA(A) receptor agonist and antagonist on morphine-induced conditioned place preference (CPP) in male Wistar rats have been investigated. Subcutaneous (s.c.) administration of different doses of morphine sulfate (1-9 mg/kg) produced a dose-dependent CPP. Using a 3-day schedule of conditioning, it was found that the GABA(A) receptor agonist, muscimol (0.125, 0.25 and 0.5 microg/rat) or the GABA(A) receptor antagonist, bicuculline (0.125, 0.25 and 0.5 microg/rat), did not produce a significant place preference or place aversion. Intra-BLA administration of muscimol (0.25 and 0.5 microg/rat) decreased the acquisition of CPP induced by morphine (6 mg/kg). On the other hand, intra-BLA injection of bicuculline (0.25 and 0.5 microg/rat) in combination with an ineffective dose of morphine (1 mg/kg) elicited a significant CPP. The response of different doses of muscimol was attenuated by bicuculline (0.125 and 0.25 microg/rat). Furthermore, intra-BLA administration of bicuculline but not muscimol before testing significantly decreased the expression of morphine (6 mg/kg)-induced place preference. The administration of the higher doses of bicuculline (0.25 and 0.5 microg/rat) during acquisition and the higher dose of muscimol (2 microg/rat) on the test day decreased the locomotor activity of the animals on the testing phase. It can be concluded that GABA(A) receptors in the amygdala are involved in morphine reward.
authors.affiliation: Department of Biology, Faculty of Science, Tehran University, Tehran, Iran. zarinmr@ams.ac.ir
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Zarrindast
authors.forename: Shamseddin
authors.initials: S
authors.lastname: Ahmadi
authors.forename: Ali
authors.initials: A
authors.lastname: Haeri-Rohani
authors.forename: Ameneh
authors.initials: A
authors.lastname: Rezayof
authors.forename: Mohammad-Reza
authors.initials: MR
authors.lastname: Jafari
authors.forename: Majid
authors.initials: M
authors.lastname: Jafari-Sabet
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001640:Bicuculline / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D012055:Reinforcement Schedule; D012201:Reward; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D000701:Analgesics, Opioid; D018755:GABA Agonists; D018756:GABA Antagonists; D011963:Receptors, GABA-A; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D009020:Morphine; D001640:Bicuculline