Pb2+ reduces the current from NMDA receptors expressed in Xenopus oocytes.
We compared the effects of Pb2+ on four types of NMDA receptors expressed in Xenopus oocytes. Pb2+ reduced the currents evoked by glutamate and glycine. The Ki values of the receptors, epsilon 1/zeta 1, epsilon 2/zeta 1, epsilon 3/zeta 1 and epsilon 4/zeta 1, were 39, 34, 54 and 42 microM, respectively, and their Hill coefficients were 0.53, 4.6, 0.52 and 0.37, respectively. The epsilon 2/zeta 1 receptor that was inhibited in the presence of over 30 microM Pb2+ was not recovered to the control level after a Pb2+ washout for over 30 min, suggesting that epsilon 2/zeta 1 is responsible for the chronic Pb2+ intoxication in the nervous system.
Department of Pharmacology, Yamaguchi University School of Medicine, Japan.
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Yamada
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Ujihara
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Sada
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Ban
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004553:Electric Conductivity; D007854:Lead / Q000494:pharmacology*; D051379:Mice; D009865:Oocytes; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects* / Q000378:metabolism; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D014981:Xenopus
D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D007854:Lead