title: Glutamic acid reverses Pb2+-induced reductions of NMDA receptor subunits in vitro.
abstract: The objective of this study is to determine the effects of Pb2+ on N-methyl-d-aspartate receptor (NMDAR) subunits--NR1C1, NR2A and NR2B in primary cultured neuronal cells. We hypothesize that L-glutamic acid (GA) reverses Pb2+-induced NMDAR damage. Neuronal cells were isolated from the fetus brain at 18-20th day of gestation of pregnant Sprague Dawley (SD) rats. All experiments were included three independent cell preparations (N=3). The neuronal cells were exposed to Pb2+ (10(-10), 10(-9), 10(-8) and 10(-7)M) for 24 h. Neurons were pretreated with NMDAR agonist--L-glutamic acid (GA) (200 microM) and antagonists dizocipine (MK-801, 50 nM) for 1h and then exposed to 10(-7)M of Pb2+ for 24 h. Finally, GA at 2, 0.2 and 0.02 mM was incubated with neurons prior to Pb2+ exposure. Aliquots of NR1, NR2A and NR2B proteins from cell homogenate were immunoprecipitated with protein A agarose and detected by Western blotting. The addition of GA unconventionally reversed the reductions of NMDAR by Pb at protein levels, whereas MK-801 exacerbated Pb2+-induced damage. The protection by GA against Pb2+-induced reduction of NMDAR was dose-dependent. These findings suggest that the administration of GA may be a potential approach to intervene the Pb2+-induced NMDAR alterations.
authors.affiliation: Department of Biological Sciences, Alcorn State University, 1000 ASU Drive, P.O. Box 870, Alcorn State, MS 39096, USA.
authors.forename: Shang-Zhi
authors.initials: SZ
authors.lastname: Xu
authors.forename: Bettaiya
authors.initials: B
authors.lastname: Rajanna
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology*; D047468:Immunoprecipitation; D007854:Lead / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects*
chemical_list: D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid; D007854:Lead; D009419:Nerve Tissue Proteins; D016194:Receptors, N-Methyl-D-Aspartate; C121001:NR2B NMDA receptor