[Effect of naloxone on the activity of Cl(-)-activated Mg(2+)-ATPase from plasma membrane fraction of the common bream brain (Abramis brama L.) in the presence of GABAa-ergic substances].
We studied the effect of naloxone--an antagonist of the opioid receptors--on sensitivity of Cl(-)-activated Mg(2+)-ATPase from the plasma membrane fraction of bream brain (Abramis brama L.) to GABAa-ergic substances. Preincubation of the plasma membranes with 1-100 microM naloxone increased the basal Mg(2+)-ATPase activity and suppressed its activation by chloride ions. The same effects were observed in the presence of the agonists of GABAa/benzodiazepine receptors: 0.1-100 microM GABA, 1-500 microM pentobarbital, and 0.1-100 microM phenazepam. Naloxone (10 microM) inhibited the activation of the basal Mg(2+)-ATPase by the studied ligands and regenerated the enzyme sensitivity to Cl-. However, the effect of naloxone was not observed in the presence of high concentrations of pentobarbital (500 microM) and phenazepam (100 microM). The obtained data show that naloxone modulates the activity of Cl(-)-activated Mg(2+)-ATPase from the plasma membranes of bream brain and antagonizes the GABAa receptor ligands.
Menzikov
S A
SA
Papanin Institute of Biology of Inland Waters, Russian Academy of Science, Borok, Yaroslavl ragion, 152742 Russia. sam@ibiw.yaroslavl.ru
Menzikova
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OV
D000818:Animals; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D017301:Ca(2+) Mg(2+)-ATPase / Q000187:drug effects / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D002712:Chlorides / Q000378:metabolism; D003530:Cyprinidae; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D018682:GABA Agents / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D014151:Anti-Anxiety Agents; D002712:Chlorides; D018682:GABA Agents; D018757:GABA Modulators; D009292:Narcotic Antagonists; D011963:Receptors, GABA-A; D001569:Benzodiazepines; D009270:Naloxone; C017928:phenazepam; D005680:gamma-Aminobutyric Acid; D017301:Ca(2+) Mg(2+)-ATPase; D010424:Pentobarbital
Vliianie naloksona na aktivnost' Cl--aktiviruemoĭ Mg2+-ATFazy fraktsii plazmaticheskikh membran mozga leshcha (Abramis brama L.) pri deĭstvii GAMKa-ergicheskikh veshchestv.