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Potassium‐Induced Depolarization of Rat Telencephalic Synaptoneurosomes Increases [ 3 H]Amino‐3‐Hydroxy‐5‐Methylisoxazole‐4‐Propionate Receptor Binding
Author(s) -
Bernard Julie,
Massicotte Guy,
Baudry Michel
Publication year - 1992
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1992.tb09323.x
Subject(s) - ampa receptor , depolarization , chemistry , biophysics , nbqx , calcium , egta , receptor , nmda receptor , biochemistry , biology , organic chemistry
Potassium‐induced depolarization of synaptoneurosomes prepared from rat telencephalon was found to increase [ 3 H]amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate ([ 3 H]AMPA) binding to the AMPA receptor. The effect required the presence of calcium because it was blocked by the calcium chelator EGTA but was not blocked by an antagonist of the N ‐methyl‐D‐aspartate receptor, aminophosphonopentanoate. The depolarization‐induced increase in [ 3 H]AMPA binding was markedly reduced by a blocker of voltage‐dependent calcium channels, verapamil. Saturation kinetic experiments revealed that the increase in [ 3 H]AMPA binding produced by potassium depolarization was due to an increase in the affinity of the AMPA receptor. These results provide additional support for a critical role of calcium in the regulation of the AMPA receptors. The syn‐aptoneurosome preparation might represent an interesting tool to determine the role of different calcium‐dependent enzymes involved in the regulation of the AMPA receptor.