Quisqualate receptor-mediated depression of calcium currents in hippocampal neurons.
The modulation of Ca2+ currents by the excitatory neurotransmitter glutamate and its analogs was investigated in hippocampal neurons in culture. In the presence of glutamate receptor-gated ion channel antagonists, all of the analogs tested caused either a small reversible depression or had no effect on the Ca2+ current. However, in neurons dialyzed with GTP gamma S, quisqualate and glutamate but not NMDA, kainate, AMPA, or L-APB caused marked and irreversible depressions of the Ca2+ current. This inhibition was only observed if Ca2+ was present in either the internal or external medium. Intracellular H-7, staurosporine, IP3, cAMP, cGMP, or calmodulin inhibitors failed to prevent the quisqualate-induced Ca2+ current inhibition. These observations are consistent with an interaction between a G protein-coupled glutamate receptor and Ca2+ channels.
Lester
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Vollum Institute, Oregon Health Sciences University, Portland 97201.
Jahr
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D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D004553:Electric Conductivity / Q000502:physiology; D019204:GTP-Binding Proteins / Q000378:metabolism; D005971:Glutamates / Q000502:physiology; D018698:Glutamic Acid; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D010069:Oxadiazoles / Q000494:pharmacology; D016318:Quisqualic Acid; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D005971:Glutamates; D009467:Neuromuscular Depolarizing Agents; D010069:Oxadiazoles; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D010566:Virulence Factors, Bordetella; D018698:Glutamic Acid; D016318:Quisqualic Acid; D019204:GTP-Binding Proteins; D002118:Calcium