title: Potentiation of the propunishment, but not the convulsant action of the beta-carboline DMCM by naltrexone.
abstract: The ability of naltrexone (NTX) to potentiate the propunishment and convulsant properties of DMCM, a benzodiazepine receptor inverse agonist, was studied in mice. Doses (0.39 and 1.56 mg/kg) of DMCM which were below the threshold for propunishment effects showed a marked ability to enhance the suppressive effects of punishment on locomotor activity in the presence of naltrexone (0.5 or 2.5 mg/kg IP), higher doses of DMCM and NTX (3.13 mg/kg and 10 mg/kg, respectively) had a depressant effect of their own on both punished and unpunished locomotor activity. DMCM given alone induced clonic convulsions (ED50: 5.7 mg/kg IP) but this activity was not changed in the presence of naltrexone. These results suggest an interaction of BZ receptors and opioid systems in the control of anxiety.
mesh_terms: D000818:Animals; D001007:Anxiety / Q000139:chemically induced; D002243:Carbolines / Q000494:pharmacology*; D004357:Drug Synergism; D005260:Female; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009271:Naltrexone / Q000494:pharmacology*; D011678:Punishment; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D012640:Seizures / Q000139:chemically induced
chemical_list: D002243:Carbolines; D011963:Receptors, GABA-A; D011957:Receptors, Opioid; C034818:methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate; D009271:Naltrexone