title: N-methyl D-aspartate receptor-mediated bidirectional control of extracellular signal-regulated kinase activity in cortical neuronal cultures.
abstract: N-Methyl D-aspartate (NMDA) receptor activation of extracellular-signal regulated kinase (ERK) was examined in primary cortical cultures. Tetrodotoxin, NMDA receptor antagonists, or reduced extracellular calcium (0.1 mm) greatly decreased basal levels of phospho-ERK2, indicating that activity-dependent activation of NMDA receptors maintained a high level of basal ERK2 activation. This activity-dependent activation of phospho-ERK2 was blocked by pertussis toxin and inhibition of calcium/calmodulin-dependent kinase II and phosphatidylinositol 3-kinase but not by inhibition of protein kinase C or cAMP-dependent protein kinase. Addition of a calcium ionophore or 100 microm NMDA decreased phospho-ERK2 in the presence of 1 mm extracellular calcium but enhanced phospho-ERK2 in 0.1 mm extracellular calcium. The reduction in basal phospho-ERK2 by 100 microm NMDA was also reflected as a decrease in phospho-cAMP response element-binding protein. Inhibition of tyrosine phosphatases and serine/threonine phosphatases protein phosphatase 1 (PP1), PP2A, and PP2B did not prevent the inhibitory effect of NMDA. In the presence of tetrodotoxin, NMDA produced a bell-shaped dose-response curve with stimulation of phospho-ERK2 at 10, 25, and 50 microm NMDA and reduced stimulation at 100 microm NMDA. NMDA (50 microm) stimulation of phospho-ERK2 was completely blocked by pertussis toxin and inhibitors of phosphatidylinositol 3-kinase and was partially blocked by a calcium/calmodulin-dependent kinase II inhibitor. These results suggests that NMDA receptors can bidirectionally control ERK signaling.
authors.affiliation: Departments of Physiology/Neuroscience and Psychiatry, Medical University of South Carolina, Charleston 29425, USA. chandj@musc.edu
authors.forename: L J
authors.initials: LJ
authors.lastname: Chandler
authors.forename: G
authors.initials: G
authors.lastname: Sutton
authors.forename: N R
authors.initials: NR
authors.lastname: Dorairaj
authors.forename: D
authors.initials: D
authors.lastname: Norwood
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008954:Models, Biological; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D054645:Protein Phosphatase 1; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D009435:Synaptic Transmission; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D016202:N-Methylaspartate; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D054645:Protein Phosphatase 1; D017346:Protein Serine-Threonine Kinases; D017027:Protein Tyrosine Phosphatases; D011505:Protein-Tyrosine Kinases; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D013755:Tetradecanoylphorbol Acetate; D010566:Virulence Factors, Bordetella