Loss of the nAChR-mediated improvement in LIDs with drug removal
MPTP-lesioned monkeys were gavaged with l-DOPA and given vehicle, nicotine, varenicline, or TC-8831 according to the treatment regimens depicted in Fig. 1 for varenicline and Fig. 3 for TC-8831. Drug removal led to a return of LIDs to vehicle-treated values by 1–6 weeks after washout. Values are the mean ± S.E.M. of the number of monkeys indicated in parentheses.
| nAChR Drug and Time Point | Total LID Scores (% Vehicle) | |
|---|---|---|
| Vehicle | nAChR Drug | |
| Varenicline | ||
| Last week treatment | 100 ± 8.8 (6) | 50 ± 4.9 (12)** |
| Week 1 washout | 100 ± 4.2 (6) | 66 ± 8.4 (12)* |
| Week 3 washout | 100 ± 7.5 (6) | 70 ± 8.6 (12) |
| Week 5 washout | 100 ± 14.9 (6) | 90 ± 4.5 (12) |
| Nicotine | ||
| Last week treatment | 100 ± 8.8 (6) | 22 ± 2.8 (5)*** |
| Week 1 washout | 100 ± 4.2 (6) | 48 ± 8.0 (5)*** |
| Week 3 washout | 100 ± 7.5 (6) | 61 ± 7.3 (5)** |
| Week 6 washout | 100 ± 14.9 (6) | 92 ± 9.6 (5) |
| TC-8831 | ||
| Last week treatment | 100 ± 8.5 (6) | 45 ± 11 (6)** |
| Week 1 washout | 100 ± 6.2 (6) | 102 ± 4.1 (6) |
↵* P < 0.05; **P < 0.01; ***P < 0.001 using a t test (significance of difference from vehicle).