PT  - JOURNAL ARTICLE
AU  - Xiao, Yingxian
AU  - Meyer, Erin L.
AU  - Thompson, Jessica M.
AU  - Surin, Alexander
AU  - Wroblewski, Jarda
AU  - Kellar, Kenneth J.
TI  - Rat α3/β4 Subtype of Neuronal Nicotinic Acetylcholine Receptor Stably Expressed in a Transfected Cell Line: Pharmacology of Ligand Binding and Function
AID  - 10.1124/mol.54.2.322
DP  - 1998 Aug 01
TA  - Molecular Pharmacology
PG  - 322--333
VI  - 54
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/54/2/322.short
4100  - http://molpharm.aspetjournals.org/content/54/2/322.full
SO  - Mol Pharmacol1998 Aug 01; 54
AB  - We stably transfected human kidney embryonic 293 cells with the rat neuronal nicotinic acetylcholine receptor (nAChR) α3 and β4 subunit genes. This new cell line, KXα3β4R2, expresses a high level of the α3/β4 receptor subtype, which binds (±)- [3H]epibatidine with aK d value of 304±16 pm and a B max value of 8942 ± 115 fmol/mg protein. Comparison of nicotinic drugs in competing for α3/β4 receptor binding sites in this cell line and the binding sites in rat forebrain (predominantly α4/β2 receptors) revealed marked differences in theirK i values, but similar rank orders of potency for agonists were observed, with the exception of anatoxin-A. The affinity of the competitive antagonist dihydro-β-erythroidine is >7000 times higher at α4/β2 receptors in rat forebrain than at the α3/β4 receptors in these cells. The α3/β4 nAChRs expressed in this cell line are functional, and in response to nicotinic agonists, 86Rb+ efflux was increased to levels 8–10 times the basal levels. Acetylcholine, (−)-nicotine, cytisine, carbachol, and (±)-epibatidine all stimulated86Rb+ efflux, which was blocked by mecamylamine. The EC50 values for acetylcholine and (−)-nicotine to stimulate 86Rb+ effluxes were 114 ± 24 and 28 ± 4 μm, respectively. The rank order of potency of nicotinic antagonists in blocking the function of this α3/β4 receptor was mecamylamine >d-tubocurarine > dihydro-β-erythroidine > hexamethonium. Mecamylamine, d-tubocurarine, and hexamethonium blocked the function by a noncompetitive mechanism, whereas dihydro-β-erythroidine blocked the function competitively. The KXα3β4R2 cell line should prove to be a very useful model for studying this subtype of nAChRs.