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Binding of specific ligands to muscarinic receptors alters the fluidity of membrane fragments from rat brain A fluorescence polarization study with lipid‐specific probes
Author(s) -
Manevich E.M.,
Köiv A.,
Järv J.,
Molotkovsky J.G.,
Bergelson L.D.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80282-5
Subject(s) - muscarinic acetylcholine receptor , fluorescence anisotropy , membrane fluidity , carbachol , chemistry , biophysics , membrane , receptor , fluorescence , radioligand assay , biochemistry , biology , physics , quantum mechanics
The previously suggested method of following ligand‐receptor interactions by measuring ligand‐induced changes in membrane fluidity [(1986) FEBS Lett. 194, 313–316] was employed to study the binding of specific ligands of the muscarinic receptor to rat brain membrane fragments containing a fluorescent analogue of phosphatidylcholine (APC) as a membrane probe. Upon addition of carbachol and atropine in low concentrations the fluorescence polarization of the APC‐labeled membranes decreased significantly demonstrating that binding of these ligands to the muscarinic receptor increases the fluidity of its lipid environment. The fluidity changes were specific, concentration‐dependent and saturable. In comparison with radioligand assays the fluorescent lipid probe method proved to be much more sensitive but the K d values obtained by the two methods differed considerably.