Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Calcium / metabolism
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Calcium / pharmacokinetics
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Calcium / physiology*
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Cell Membrane / physiology
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Cell Membrane / ultrastructure
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Cell Membrane Permeability / drug effects
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Cell Membrane Permeability / physiology
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Electric Conductivity / physiology
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GTP-Binding Proteins / metabolism
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Glutamates / physiology
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Glutamic Acid
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Hippocampus / metabolism
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Hippocampus / physiology*
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Humans
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Membrane Potentials / drug effects
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Membrane Potentials / physiology
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Neuromuscular Depolarizing Agents / pharmacology
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Neurons / metabolism
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Neurons / physiology*
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Neurons / ultrastructure
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Oxadiazoles / pharmacology
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Quisqualic Acid
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Receptors, AMPA
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Receptors, Glutamate
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Receptors, Neurotransmitter / drug effects
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Receptors, Neurotransmitter / metabolism
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Receptors, Neurotransmitter / physiology*
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Second Messenger Systems / drug effects
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Second Messenger Systems / physiology
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Virulence Factors, Bordetella / pharmacology
Substances
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Glutamates
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Neuromuscular Depolarizing Agents
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Oxadiazoles
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Receptors, AMPA
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Receptors, Glutamate
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Receptors, Neurotransmitter
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Virulence Factors, Bordetella
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Glutamic Acid
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Quisqualic Acid
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GTP-Binding Proteins
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Calcium