title: Interactions between NMDA receptors and mGlu5 receptors expressed in HEK293 cells.
abstract: 1 Ca2+ imaging was used to investigate interactions between responses induced by N-methyl-D-aspartate (NMDA; 15 microm) and (RS)-3,5-dihydroxyphenyl-glycine (DHPG; 30 microm) in human embryonic kidney (HEK) 293 cells, transiently transfected with rat recombinant NR1a, NR2A and mGlu5a cDNA. 2 Responses to NMDA were reversibly depressed by DHPG from 244+/-14 to 194+/-12% of baseline. Treatment with thapsigargin (1 microm, 10 min) prevented this effect. 3 After thapsigargin pretreatment, repeated applications of NMDA showed a gradual rundown in amplitude over a period of several hours, and were unaffected by DHPG. 4 Continuous perfusion with staurosporine (0.1 microm), after thapsigargin pretreatment, converted the run-down to a small increase in NMDA responses to 123+/-6 % of baseline. DHPG induced a further and sustained potentiation of NMDA responses to 174+/-12% of the initial baseline. 5 The protein tyrosine kinase (PTK) inhibitors genistein (50 microm) and 3-(4-chlorophenyl)1-(1,1-dimethylethyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP2; 1 microm) inhibited the staurosporine- and DHPG-induced potentiation of NMDA responses. 6 The protein phosphatase (PTP) inhibitors orthovanadate (100 microm) and phenyl arsine oxide (PAO, 1 microm) facilitated the staurosporine-evoked potentiation of NMDA responses and occluded DHPG-induced potentiation. 7 In conclusion, complex interactions can be demonstrated between mGlu5 and NMDA receptors expressed in HEK293 cells. There is a negative inhibitory influence of Ca2+ release and PKC activation. Inhibition of these processes reveals a tonic, mGlu5 receptor and PTK-dependent potentiation of NMDA receptors that can be augmented by either stimulating mGlu5 receptors or by inhibiting PTPs.
authors.affiliation: MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD. V.J.Collett@bristol.ac.uk
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Collett
authors.forename: Graham L
authors.initials: GL
authors.lastname: Collingridge
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D002460:Cell Line; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D015870:Gene Expression; D019833:Genistein / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D016202:N-Methylaspartate / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D020239:Receptor Cross-Talk / Q000187:drug effects / Q000502:physiology; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D012118:Resorcinols / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology
chemical_list: D001152:Arsenicals; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D011993:Recombinant Fusion Proteins; D012118:Resorcinols; C029341:oxophenylarsine; D014638:Vanadates; D014443:Tyrosine; C079215:3,5-dihydroxyphenylglycine; D016202:N-Methylaspartate; D019284:Thapsigargin; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D019311:Staurosporine; D005998:Glycine