Effect of varying doses of Dyn A-(2-17) i.v. on the sensitivity to morphine coadministered spinally and supraspinally at the fixed ratio of 1:10 in mice rendered tolerant to morphine by pellet implantation
| Doses of Dyn A-(2-17) (μmol/kg) | Apparent AD50 +S.E. Values of Morphine (nmol/mouse)2-a | |
|---|---|---|
| i.t.2-a | i.c.v.2-a | |
| None | 0.52 ± 0.063 | 5.2 ± 0.63 |
| 2.1 | 0.50 ± 0.13 | 5.0 ± 1.3 |
| 4.2 | 0.36 ± 0.09 | 3.6 ± 0.9 |
| 8.4 | 0.20 ± 0.05 | 2.0 ± 0.5 |
↵2-a Significant linear regression of AD50 on dose (P < .005).