Table 1.
Comparison of Ki values for nicotine, cytisine and 3-IC inhibition of [125I]epibatidine binding in total membrane preparation from inferior colliculi of wild-type, β2-/- and β4-/- C57BL/6J mice. Same compounds were also tested for inhibition of [125I]α-bungarotoxin binding in hippocampus of wild-type C57BL/6J mice. Data represent mean ± SEM of 3 independent experiments, each with triplicate samples. The concentration of [125I]epibatidine and [125I]α-bungarotoxin was 200 pM and 0.5 nM respectively. The Kd values used to calculate Ki was 30 pM for [125I]epibatidine and 0.5 nM for [125I]α-bungarotoxin.
| [125I]α-bungarotoxin (WT) Ki (μM) | [125I]epibatidine (WT) Ki (nM) | [125I]epibatidine (β2 -/-) Ki (nM) | [125I]epibatidine (β4 -/-) Ki (nM) | ||
|---|---|---|---|---|---|
| low | high | ||||
| nicotine | 0.93 ± 0.10 | 25.0 ± 21.0 | 1.29 ± 0.41 | 23.9 ± 6.2 | 1.67 ± 0.13 |
| cytisine | 1.58 ± 0.18 | 14.4 ± 1.5 | 0.24 ± 0.01 | 9.7 ± 1.5 | 0.35 ± 0.01 |
| 3-IC | 0.0022 ± 0.0012 | 1.36 ± 0.05 | 0.85 ± 0.02 | 0.25 ± 0.04 | 0.128 ± 0.003 |