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Genetically-encoded Molecular Probes to Study G Protein-coupled Receptors
Published on: September 13, 2013
Agonist-stimulated [35S]GTPgammaS autoradiography: optimization for high sensitivity
H K Happe1, D B Bylund, L C Murrin
1Department of Pharmacology, University of Nebraska Medical Center, 986260 Nebraska Medical Center, 600 South 42nd Street, Omaha, NE 68198-6260, USA.
European Journal of Pharmacology
|June 30, 2001
Summary
Optimized autoradiography assays enhance visualization of G protein-coupled receptor activity. These improved methods increase sensitivity for studying receptor-G protein interactions in rat brain tissue.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Guanosine triphosphate gamma-S ([35S]GTPgammaS) binding assays measure G protein-receptor coupling.
- Autoradiography is a key technique for visualizing receptor binding in tissue sections.
- Previous methods had limitations in sensitivity for detecting low-level receptor-G protein interactions.
Purpose of the Study:
- To optimize assay conditions for enhanced sensitivity in [35S]GTPgammaS autoradiography.
- To improve the visualization of functional G protein-receptor coupling in rat brain sections.
- To extend the utility of this assay for receptors with low basal or stimulated binding.
Main Methods:
- Optimization of buffer composition (glycylglycine), incubation time, and reagent concentrations.
- Measurement of non-specific binding (NSB), basal, and agonist-stimulated [35S]GTPgammaS binding.
- Utilized methadone, 5-carboxamidotryptamine, and epinephrine for mu-opiate, 5-HT(1A), and alpha(2)-adrenoceptors, respectively.
Main Results:
- Achieved a two- to threefold improvement in sensitivity for [35S]GTPgammaS autoradiography.
- Glycylglycine buffer, dithiothrietol, extended incubation, GDP preincubation, and low [35S]GTPgammaS concentration reduced NSB and basal binding.
- Enhanced signal-to-noise ratio allowed for clearer observation of agonist-stimulated binding.
Conclusions:
- Optimized assay conditions significantly improve the sensitivity of [35S]GTPgammaS autoradiography.
- This enhanced technique facilitates the study of receptor-G protein coupling, even for receptors with low binding levels.
- The improved method broadens the application of autoradiography for investigating receptor pharmacology and function.
