| Autor: |
Gopalakrishnan, Murali, Buisson, Bruno, Touma, Edward, Giordano, Tony, Campbell, Jeff E., Hu, Iris C., Donnelly-Roberts, Diana, Arneric, Stephen P., Bertrand, Daniel, Sullivan, James P. |
| Zdroj: |
European Journal of Pharmacology: Molecular Pharmacology; 19950123, Vol. 290 Issue: 0 p237-246, 10p |
| Abstrakt: |
The α 7 neuronal nicotinic acetylcholine receptor subtype forms a Ca-permeable homooligomeric ion channel sensitive to α-bungarotoxin in Xenopus oocytes. In this study, we have stably and functionally expressed the human α 7 cDNA in a mammalian cell line, HEK-293 and examined its pharmacologic properties. [ 125 I]α-Bungarotoxin bound to transfected cellswith a K d value of 0.7 nM and a B max value of 973 pmol/mg protein. No specific binding was detected in untransfected cells. Specific binding could be displaced by unlabeled α-bungarotoxin ( K i = 0.5 nM and an excellent correlation was observed between binding affinities of a series of nicotinic cholinergic ligands in transfected cells and those in the human neuroblastoma IMR-32 cell line. Additionally, cell surface expression of α 7 receptors was detected by fluorescein isothiocyanate-conjugated α-bungarotoxin in transfected cells. Whole cell currents sensitive to blockade by α-bungarotoxin, and with fast kinetics of activation and inactivation, were recorded from transfected cells upon rapid application of (−)-nicotine or acetylcholine with EC 50 values of 49 μM and 155 μM respectively. We conclude that the human α 7 subunit when expressed alone can form functional ion channels and that the stably transfected HEK-293 cell line serves as a unique system for studying human μ 7 nicotinic receptor function and regulation, and for examining ligand interactions. |
| Databáze: |
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