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11:45
Quantifying Agonist Activity at G Protein-coupled Receptors
Published on: December 26, 2011
The relationship between agonist potency and AMPA receptor kinetics
Wei Zhang1, Antoine Robert, Stine B Vogensen
1Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066, USA.
Biophysical Journal
|May 30, 2006
Summary
AMPA receptor kinetics differ based on agonist potency, influencing synaptic transmission. Ligand binding and recovery from desensitization reveal complex, multi-component behaviors in GluR2 channels.
Area of Science:
- Neuroscience
- Molecular Biology
- Biophysics
Background:
- AMPA-type glutamate receptors are crucial for fast excitatory synaptic transmission.
- Agonist binding to receptor subunits triggers channel opening through conformational changes.
Purpose of the Study:
- To compare the kinetic behavior of GluR2 channels activated by four different full agonists.
- To investigate the influence of agonist potency on receptor deactivation, desensitization, and recovery kinetics.
Main Methods:
- Electrophysiological recordings of GluR2 channels.
- Application of four full agonists (glutamate, AMPA, quisqualate, 2-Me-Tet-AMPA) with varying potencies.
- Use of cyclothiazide to reduce desensitization.
Main Results:
- Deactivation kinetics were strongly agonist-dependent, with slower decays correlating with increased agonist potency.
- Desensitization decays were similar across agonists but showed multiple exponential components.
- Recovery from desensitization exhibited two sigmoid components, with recovery speed varying significantly by agonist and increasing with potency.
Conclusions:
- Multiple kinetic components in AMPA receptor function likely originate from pre-gating closed-state transitions.
- Agonist potency significantly impacts receptor deactivation and recovery from desensitization.
- Stargazin modulates these kinetic components, potentially influencing excitatory postsynaptic current dynamics.
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