title: Effect of activity at metabotropic, as well as ionotropic (NMDA), glutamate receptors on morphine dependence.
abstract: 1. The contribution of various excitatory amino acid (EAA) receptors (NMDA, AMPA/kainate and metabotropic) in the brain to the development of morphine dependence was examined. This was performed by measuring the severity of the precipitated withdrawal syndrome following chronic subcutaneous (s.c.) morphine and intracerebroventricular (i.c.v.) EAA antagonist treatment. 2. Continuous subcutaneous (s.c.) treatment with morphine sulphate (36.65 mumol day-1) produced an intense and reliable naloxone-precipitated withdrawal syndrome. 3. Chronic i.c.v. treatment with antagonists selective for metabotropic and NMDA receptors, but not AMPA/kainate receptors, significantly attenuated abstinence symptoms. Conversely, EAA antagonists had very little effect on non-withdrawal behaviours. 4. These results suggest that, as well as changes elicited by activation of NMDA receptors, metabotropic receptors and intracellular changes in the phosphatidylinositol (PI) second-messenger system or the cyclic adenosine 3',5'-monophosphate (cAMP) second messenger system, to which EAA metabotropic receptors are linked, may be involved in the development of opioid dependence with chronic morphine treatment.
authors.affiliation: Pain Mechanisms Laboratory, Clinical Research Institute of Montreal, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Fundytus
authors.forename: T J
authors.initials: TJ
authors.lastname: Coderre
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents; D001522:Behavior, Animal / Q000187:drug effects; D001565:Benzoates / Q000494:pharmacology; D001569:Benzodiazepines / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D009021:Morphine Dependence / Q000188:drug therapy* / Q000523:psychology; D051381:Rats; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000187:drug effects*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000187:drug effects*; D013375:Substance Withdrawal Syndrome / Q000523:psychology
chemical_list: D000409:Alanine; D014151:Anti-Anxiety Agents; D001565:Benzoates; D001569:Benzodiazepines; D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D005998:Glycine; D009020:Morphine; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C000211:2-amino-3-phosphonopropionic acid; C061950:GYKI 52466; C079693:4-carboxyphenylglycine