title: Effects of CNQX and MPEP on sensitization to the rewarding effects of morphine.
abstract: The present study was conducted to evaluate the influence of the glutamatergic receptors α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and metabotropic glutamate 5 (mGlu5) receptors on sensitization to the rewarding effects of morphine. The effects of pre-treatment with saline or 20mg/kg morphine plus the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (5 or 10mg/kg) or the metabotropic Glu5 receptor antagonist 6-methyl-2-(phenylethynyl)-pyridine (MPEP) (5 or 10mg/kg) on the place conditioning induced by a low dose of morphine (2mg/kg) were assessed. The 2mg/kg dose of morphine was ineffective in animals pre-treated with saline but induced a clear conditioned place preference (CPP) in mice pre-treated with morphine alone and morphine plus any of the MPEP doses or the lowest dose of CNQX. Conversely, animals pre-treated with morphine plus 10mg/kg of CNQX did not acquire CPP. Our results suggest that AMPA glutamate receptors are involved in the development of sensitization to the conditioned rewarding effects of morphine.
authors.affiliation: Unidad de Investigación Psicobiología de las Drogodependencias, Departamento de Psicobiología, Facultad de Psicología, Universitat de València, Av. Blasco Ibañez 21, Valencia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Manzanedo
authors.forename: María A
authors.initials: MA
authors.lastname: Aguilar
authors.forename: José
authors.initials: J
authors.lastname: Miñarro
authors.forename: Marta
authors.initials: M
authors.lastname: Rodríguez-Arias
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D051379:Mice; D009020:Morphine / Q000008:administration & dosage*; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology; D064529:Receptor, Metabotropic Glutamate 5; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012201:Reward
chemical_list: D018691:Excitatory Amino Acid Antagonists; D011725:Pyridines; D064529:Receptor, Metabotropic Glutamate 5; D018091:Receptors, AMPA; D018094:Receptors, Metabotropic Glutamate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D009020:Morphine; C121465:6-methyl-2-(phenylethynyl)pyridine