title: Interaction between metals and chelating agents affects glutamate binding on brain synaptic membranes.
abstract: The present study investigates the possible effects of Hg2+, Pb2+, and Cd2+ on [3H]-glutamate binding. To better understand the role of the thiol-disulfide status on the toxicity of such metals toward glutamatergic neurotransmission, we used three thiol chelating agents, 2,3-dimercaptopropanol (BAL), 2,3-dimercaptopropane 1-sulfonate (DMPS), and meso-2,3-dimercaptosuccinic acid (DMSA). Dithiotreitol (DTT) was tested for its ability to prevent metals-induced inhibition on [3H]-glutamate binding. Hg2+, Pb2+, and Cd2+ showed a concentration-dependent inhibition on [3H]-glutamate binding, and mercury was the most effective inhibitor. BAL did not prevent [3H]-glutamate binding inhibition by Hg2+, Cd2+, and Pb2+. However, DMPS and DMSA prevented the inhibition caused by Cd2+ and Pb2+, but not by Hg2+. DTT did not prevent the inhibition on [3H]-glutamate binding caused by 10 microM Hg2+. In contrast, it was able to partially prevent [3H]-glutamate binding inhibition caused by 40 microM Pb2+ and Cd2+. These results demonstrated that the heavy metals present an inhibitory effect on [3H]-glutamate binding. In addition, BAL was less effective to protect [3H]-glutamate binding inhibition caused by these metals than other chelating agents studied.
authors.affiliation: Departamento de Bioquimica, ICBS, Universidade Federal do Rio Grande do Sul, RS, Brazil.
authors.forename: Félix Antunes
authors.initials: FA
authors.lastname: Soares
authors.forename: Marcelo
authors.initials: M
authors.lastname: Farina
authors.forename: Francielli Weber
authors.initials: FW
authors.lastname: Santos
authors.forename: Diogo
authors.initials: D
authors.lastname: Souza
authors.forename: João Batista Teixeira
authors.initials: JB
authors.lastname: Rocha
authors.forename: Cristina Wayne
authors.initials: CW
authors.lastname: Nogueira
mesh_terms: D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002614:Chelating Agents / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013570:Synaptic Membranes / Q000378:metabolism*; D014316:Tritium
chemical_list: D002614:Chelating Agents; D008670:Metals; D014316:Tritium; D018698:Glutamic Acid