Journal article
The Relationship between Agonist Potency and AMPA Receptor Kinetics
Biophysical journal, Vol.91(4), pp.1336-1346
2006
DOI: 10.1529/biophysj.106.084426
PMCID: PMC1518651
PMID: 16731549
Abstract
AMPA-type glutamate receptors are tetrameric ion channels that mediate fast excitatory synaptic transmission in the mammalian brain. When agonists occupy the binding domain of individual receptor subunits, this domain closes, triggering rearrangements that couple agonist binding to channel opening. Here we compare the kinetic behavior of GluR2 channels activated by four different ligands, glutamate, AMPA, quisqualate, and 2-Me-Tet-AMPA, full agonists that vary in potency by up to two orders of magnitude. After reduction of desensitization with cyclothiazide, deactivation decays were strongly agonist dependent. The time constants of decay increased with potency, and slow components in the multiexponential decays became more prominent. The desensitization decays of agonist-activated currents also contained multiple exponential components, but they were similar for the four agonists. The time course of recovery from desensitization produced by each agonist was described by two sigmoid components, and the speed of recovery varied substantially. Recovery was fastest for glutamate and slowest for 2-Me-Tet-AMPA, and the amplitude of the slow component of recovery increased with agonist potency. The multiple kinetic components appear to arise from closed-state transitions that precede channel gating. Stargazin increases the slow kinetic components, and they likely contribute to the biexponential decay of excitatory postsynaptic currents.
Details
- Title: Subtitle
- The Relationship between Agonist Potency and AMPA Receptor Kinetics
- Creators
- Wei Zhang - Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066Antoine Robert - Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066Stine B Vogensen - Department of Medicinal Chemistry, the Danish University of Pharmaceutical Sciences, DK 2100 Copenhagen, DenmarkJames R Howe - Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066
- Resource Type
- Journal article
- Publication Details
- Biophysical journal, Vol.91(4), pp.1336-1346
- Publisher
- Elsevier Inc
- DOI
- 10.1529/biophysj.106.084426
- PMID
- 16731549
- PMCID
- PMC1518651
- ISSN
- 0006-3495
- eISSN
- 1542-0086
- Language
- English
- Date published
- 2006
- Academic Unit
- Surgery
- Record Identifier
- 9984051578602771
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