TABLE 3

Relative selectivity of nicotinic ligands for nAChRs containing β2 versus β4 subunits Selectivity was measured by the binding affinity ratios in membrane homogenates from the six stably transfected cell lines and rat forebrain. The affinity ratios were calculated from the Ki values in Table 2.

Ligand
Ki Ratio
α2β4/α2β2
α3β4/α3β2
α4β4/α4β2
α3β4/Forebrain
(±)-Epibatidine 4 16 3 10
(±)-I-Epibatidine 1 5 1 3
Acetylcholine 10 15 2 19
(-)-Nicotine 9 9 4 37
Cytisine 5 6 1 120
A-85380 250 370 58 310
I-A-85380 1300 600 410 2500
Carbachol 4 4 2 10
DMPP 44 23 33 8
Choline 2 1 1 1
DHβE 31 29 28 850
MLA
2
2
0.2
0.3