Antinociceptive effect of morphine or DVL2DAL5LanEnk given i.t. or i.p. alone or after pretreatment with NTI, a δ receptor antagonist, or CTOP, a μ receptor antagonist
| Agonist | Agonist Alone | Agonist + NTI3-150 | Agonist + CTOP3-150 |
|---|---|---|---|
| i.t. morphine (30 μg) | 93 ± 6 | 89 ± 9 | 12 ± 83-159 |
| i.t. DVL 2DAL 5LanEnk (30 μg) | 92 ± 9 | 23 ± 43-159 | 81 ± 12 |
| i.p. morphine (3 mg/kg) | 85 ± 6 | N.D. | N.D. |
| i.p. DVL 2DAL 5LanEnk (3 mg/kg) | 81 ± 7 | 21 ± 63-159 | N.D. |
Nociception is assessed as thermal escape latency time and antinociception expressed as peak %MPE ± S.E.M.
N.D., not done.
↵3-150 Antagonists given i.t. versus i.t. agonists and i.p. versus i.p. agonists; i.t. NTI = 30 μg; i.p. NTI = 1 mg/kg; i.t. CTOP = 3 μg.
↵3-159 p < 0.05 paired ttest versus predrug baseline; n = 5–6/treatment group. All agonist effects were completely reversed by naloxone 1 mg/kg i.p.; data not shown.