Cytisine sensitivity of 125I-α-conotoxin MII binding in four forebrain areas of rats continuously self-administering nicotine and of control rats Particulates from four individual animals were compared in each group. The binding values are given in fmol/mg particulate protein at 0.5 nM 125I-Cntx, corrected for the binding at 10 μM (+)-cytisine plus 100 μM (–)-nicotine. The percentage increase for nicotine self-administering over the corresponding control group is shown below the binding data at each concentration of cytisine. Asterisks indicate the significance (*, p < 0.05; **, p < 0.01) of differences between the mean values for nicotine self-administering vs. control groups in t tests.
| Area | Binding without Cytisine | Binding at 25 nM Cytisine | Binding at 250 nM Cytisine | |||
|---|---|---|---|---|---|---|
| Control | Nicotine | Control | Nicotine | Control | Nicotine | |
| Nucleus accumbens | 3.8 ± 0.15 | 6.3 ± 0.36** | 2.3 ± 0.14 | 4.8 + /-0.3** | 0.92 ± 0.14 | 2.7 ± 0.3** |
| % Increase | 64.8 ± 3.7 | 107.5 ± 7.4 | 188.5 ± 23 | |||
| Thalamus | 5.1 ± 0.3 | 13.7 ± 0.8 ** | 3.7 ± 0.31 | 12.3 ± 0.8** | 1.83 ± 0.31 | 7.9 ± 0.72** |
| % Increase | 167.6 ± 9.8 | 232 ± 15 | 332 ± 30 | |||
| Parietal cortex | 1.7 ± 0.05 | 2.08 ± 0.12 * | 1.0 ± 0.049 | 1.36 ± 0.12* | 0.33 ± 0.05 | 0.55 ± 0.11* |
| % Increase | 20.9 ± 1.2 | 36 ± 3.1 | 64.6 ± 2.9 | |||
| Hippocampus | 2.93 ± 0.3 | 3.34 ± 0.13 | 2.04 ± 0.37 | 2.46 ± 0.12 | 0.678 ± 0.24 | 1.08 ± 0.11* |
| % Increase | 14 ± 0.5 | 20.6 ± 1 | 59 ± 6.1 | |||