Potassium-induced depolarization of rat telencephalic synaptoneurosomes increases [3H]amino-3-hydroxy-5-methylisoxazole-4-propionate receptor binding.
Potassium-induced depolarization of synaptoneurosomes prepared from rat telencephalon was found to increase [3H]amino-3-hydroxy-5-methylisoxazole-4-propionate ([3H]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 [3H]AMPA binding was markedly reduced by a blocker of voltage-dependent calcium channels, verapamil. Saturation kinetic experiments revealed that the increase in [3H]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 synaptoneurosome preparation might represent an interesting tool to determine the role of different calcium-dependent enzymes involved in the regulation of the AMPA receptor.
Department of Biological Chemistry, University of Quebec at Trois-Rivières, Canada.
J
J
Bernard
G
G
Massicotte
M
M
Baudry
D000818:Animals; D002118:Calcium / Q000502:physiology; D004533:Egtazic Acid / Q000494:pharmacology; D004594:Electrophysiology; D007051:Ibotenic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism / Q000502:physiology*; D013687:Telencephalon / Q000378:metabolism / Q000502:physiology*; D014700:Verapamil / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D018091:Receptors, AMPA; D017981:Receptors, Neurotransmitter; D007051:Ibotenic Acid; D004533:Egtazic Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D014700:Verapamil; D011188:Potassium; D002118:Calcium