Characterization of noncholinergic nicotine receptors on human granulocytes.
Publication/Presentation Date
7-15-1986
Abstract
The noncholinergic nicotine receptor on leukocytes identified earlier [Davies et al., Molec. Cell. Biochem. 44, 23 (1982)] was further characterized. Structure-activity relationships showed that a pyrrolidine ring containing a basic N atom is an important structural feature for ligands that bind to the receptor. Accordingly, the carcinogenic component of tobacco smoke, N-nitrosonornicotine, does not bind to the receptor. The stereoselectivity for the d-isomer, which was confirmed using [3H]d-nicotine as a ligand, together with the absolute configurational relationship between d-nicotine and L-proline, suggested that basic peptides containing proline as the N-terminal amino acid would bind to the receptor. The finding that Pro-Lys-Pro-Arg, which has been reported to inhibit granulocyte phagocytosis, bound to the receptor with an IC50 value of 3.5 microM is compatible with this idea. An increase in receptor binding, which was observed in the presence of plasma, could be ascribed to bicarbonate. The presence of bicarbonate in the binding assay, even when the pH of the buffer was carefully controlled, resulted in an increase (approximately 2-fold) in the apparent number of receptors without affecting the Kd value significantly. Increasing the pH of the buffer in the absence of bicarbonate also increased receptor binding, suggesting that bicarbonate may increase receptor binding by its known ability to increase intracellular pH at constant extracellular pH. Preincubation of cells with d-nicotine under certain conditions reduced the subsequent binding of [3H]d-nicotine to the receptor.
Volume
35
Issue
14
First Page
2367
Last Page
2372
ISSN
0006-2952
Published In/Presented At
Hoss, W., Lin, J. P., Matchett, S., & Davies, B. D. (1986). Characterization of noncholinergic nicotine receptors on human granulocytes. Biochemical pharmacology, 35(14), 2367–2372. https://doi.org/10.1016/0006-2952(86)90463-6
Disciplines
Medicine and Health Sciences
PubMedID
3729993
Department(s)
Department of Medicine
Document Type
Article