Summary of the potency of metanicotine compared with (−)-nicotine in behavioral models and receptor binding
| Pharmacological Effect or Test | ED50 | Potency Ratio M/N1-a | |
|---|---|---|---|
| (−)-Nicotine | Metanicotine | ||
| mg/kg | |||
| Tail-flick after s.c. | 1.5 (0.9–1.8) | 7.2 (3.6–14.0) | 4.8 |
| Tail-flick after i.t. | 12.0 (10.5–17.0)1-b | 4 (2.6–5.6)1-b | 0.3 |
| Tail-flick after i.c.v. | 14.0 (9–20)1-b | 9.0 (6.7–11.8)1-b | 0.6 |
| Hot-plate | 0.50 (0.43–0.49) | 50% @ 40 | >80 |
| PPQ test | 0.2 (0.1–0.37) | 1.6 (0.55–4.4) | 8 |
| Formalin test—phase 1 | 0.25 (0.18–0.28) | 5.4 (5.0–5.9) | 21.6 |
| Formalin test—phase 2 | 0.75 (0.35–1.05) | 3 (2.6–3.6) | 4 |
| Paw pressure—nonarthritic rats | 0.03 (0.02–0.04) | 1.9 (1.2–3.1) | 63.3 |
| Paw pressure—arthritic rats | 0.05 (0.04–.07) | 3.7 (2.3–5.9) | 74 |
| Hypothermia | 1.2 (0.5–2.2) | 82 (75.5–97.0) | 68.3 |
| Hypomotility | 0.60 (0.5–0.72) | 2% @42 | >70 |
| Drug discrimination | 0.3 (0.1–0.6) | 1.9 (0.65–5.6) | 6.3 |
| Ki | |||
| nM | |||
| Receptor affinity | 1.4 ± 0.20 | 24 ± 12 | 17.1 |
ED50 values (± CL) were calculated from dose-response curve of the respective compounds and expressed as milligrams per kilogram. Each dose group included six to eight animals.