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Ganglionic nAChRs and high‐affinity nicotinic binding sites are not equivalent
Author(s) -
Kemp George,
Morley Barbara J.
Publication year - 1986
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(86)80910-3
Subject(s) - nicotinic agonist , acetylcholine receptor , nicotine , binding site , acetylcholine , chemistry , alpha 4 beta 2 nicotinic receptor , ganglion type nicotinic receptor , receptor , nicotinic antagonist , biophysics , nicotinic acetylcholine receptor , endocrinology , biology , biochemistry , neuroscience
High‐affinity ( K d ⋍ 10 nM) binding sites for nicotine and acetylcholine (ACh) have recently been identified in vertebrate brain. It has been suggested that these sites are desensitized ganglionic (C6) nicotinic acetylcholine receptors (nAChRs). We have tested the pheochromocytoma cell line PC 12, which is known to contain well‐expressed C6 nAChRs, to determine if these nAChRs are associated with high‐affinity [ 3 H]ACh‐binding sites. We found that the high‐affinity nicotinic [ 3 H]ACh‐binding site is absent in PC 12 cells. We also found that the concentration of nicotine or ACh necessary to desensitize carbamylcholine‐stimulated Na + flux was at least two orders of magnitude greater than the concentrations used in binding experiments. We conclude that high‐affinity nicotinic binding sites are not equivalent to C6 ganglionic receptors.