51. Sulfate- and size-dependent polysaccharide modulation of AMPA receptor properties
- Author
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Linda M. Chicoine, Gerald Gianutsos, Ben A. Bahr, Thirumalini Vaithianathan, and Vishnu Suppiramaniam
- Subjects
medicine.drug_class ,chemistry.chemical_element ,AMPA receptor ,Calcium ,Hippocampus ,Calcium in biology ,Rats, Sprague-Dawley ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,medicine ,Animals ,Receptors, AMPA ,Receptor ,Cells, Cultured ,6-Cyano-7-nitroquinoxaline-2,3-dione ,Neurons ,Microscopy, Confocal ,Dextran Sulfate ,Receptor antagonist ,Rats ,Dextran ,chemistry ,Biochemistry ,CNQX ,Biophysics ,NMDA receptor ,Excitatory Amino Acid Antagonists - Abstract
Previous work found evidence that α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors interact with and are functionally regulated by the glycosaminoglycan heparin. The present study tested whether dextran species affect ligand binding, channel kinetics, and calcium permeability of AMPA receptors. Dextran sulfate of 500 kDa markedly reduced high affinity [3H]AMPA binding in solubilized hippocampal membranes. In isolated receptors reconstituted in a lipid bilayer, the same dextran sulfate prolonged the lifetime of open states exhibited by AMPA-induced channel fluctuations. The large polysaccharide further changed the single channel kinetics by increasing the open channel probability five- to sixfold. Such modulation of channel activity corresponded with enhanced levels of calcium influx as shown in hippocampal neurons loaded with Fluo3AM dye. With an exposure time of
- Published
- 2004