Premium
Novel Photoactivatable Agonist of the Nicotinic Acetylcholine Receptor of Potential Use for Exploring the Functional Activated State
Author(s) -
KotzybaHibert F.,
Kessler P.,
Zerbib V.,
Bogen C.,
Snetkov V.,
Takeda K.,
Goeldner M.,
Hirth C.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.67062557.x
Subject(s) - allosteric regulation , torpedo , chemistry , acetylcholine receptor , agonist , acetylcholine , cholinergic , nicotinic agonist , nicotinic acetylcholine receptor , photoaffinity labeling , binding site , biophysics , receptor , alpha 4 beta 2 nicotinic receptor , ligand (biochemistry) , partial agonist , stereochemistry , biochemistry , pharmacology , neuroscience , biology
The nicotinic acetylcholine receptor (AChR) exhibits at least four different conformational states varying in affinity for agonists such as acetylcholine (ACh). Photoaffinity labeling has been previously used to elucidate the topography of the AChR. However, to date, the photosensitive probes used to explore the cholinergic binding site photolabeled only closed or desensitized states of the receptor. To identify the structural modifications occurring at the ACh binding site on allosteric transition associated with receptor activation, we have investigated novel photoactivatable 4‐diazocyclohexa‐2,5‐dienone derivatives as putative cholinergic agonists. Such compounds are fairly stable in the dark and generate highly reactive carbenic species on irradiation. In binding experiments using AChRs from Torpedo marmorata , these ligands had affinities for the ACh binding site in the micromolar range and did not interact with the noncompetitive blocker site (greater than millimolar affinity). Irreversible photoinactivation of ACh binding sites was obtained with the ligand 1b (up to 42% at 500 µ M ) in a protectable manner. In patch‐clamp studies, 1b was shown to be a functional agonist of peripheral AChR in TE 671 cells, with the interesting property of exhibiting no or very little desensitization even at high concentrations.