Table 1

Regulation of human α4β2 nAChRs in HEK 293 cells by cholinergic channel ligands

CompoundConcentrationUp-regulation (EC50)Binding affinity1-a
μm Ki nm
Activator
 A-853800.0001–100.008  ± 0.0010.05
 ABT-4180.001–10010.47  ± 4.507.89
 (−)-Cytisine0.001–104.00  ± 1.940.44
 DMPP0.001–10012.47  ± 2.4010.71
 (±)-Epibatidine0.0001–100.010  ± 0.0020.07
 (+)-Nicotine0.01–1004.61  ± 1.1026.25
 (−)-Nicotine0.001–1000.49  ± 0.181.05
Antagonist
d-Tubocurarine0.001–300>3003481
 DHβE1–1000107.0  ± 38.5160.13
 Mecamylamine0.01–100N.E.1-b >10,000

Values are mean ± standard error from three to five separate determinations, each performed in duplicate. Cells were grown in six-well multiwell plates and treated with varying concentrations of the compounds for 168 hr. Binding assays were performed with [3H]cytisine, (6 nm) using membranes prepared from the samples as described in Materials and Methods.

    • 1-a Ki values are from Ref. 7 except for A-85380, which is from Ref. 21.

    • 1-b N.E., no effect.