Table 2.
Comparison of ED50 values (nmol (95% CI)) for spinal morphine, DeltII and DAMGO in WT and α2A-KO mice in the tail immersion and SP behavioral assays.
| Assay | Strain | Clonidine | Morphine | DeltII | DAMGO |
|---|---|---|---|---|---|
| Tail immersion assay | WT | 4.2 (2.0–4.7) |
3.1 (2.0–4.7) |
21.2 (11.4–39.2) |
0.17 (0.09–0.32) |
| α2A-KO | N/A§ | 0.26 (0.18–0.38) |
4.3 (3.4–5.5) |
0.06 (0.03–0.10) |
|
| Potency ratio | N/A | 12:1* | 5:1* | 3:1* | |
| SP behavioral assay | WT# | 0.4 (0.2–0.7) |
0.93 (0.52–1.66) |
0.15 (0.05–0.44) |
0.0034 (0.0017–0.007) |
| α2A-KO | 7.0§ (2.9–16.6) |
0.12 (0.03–0.46) |
0.0021 (0.0006–0.008) |
0.0041 (0.0026–0.0065) |
|
| Potency ratio | 1:18* | 8:1* | 70:1* | 1:1 | |
| α2C-WT | 21.4 (9–51) |
||||
| α2C-WT | 12.5 (4.5–35) |
*
ED50 significantly different, WT vs. α2A-KO, t-test (p < 0.05)
§
Efficacy < 50%.
#
Values reported in Chabot-Doré et al. (2013)