TABLE 1

Comparison of scratching responses evoked by selective MOR, KOR, and DOR agonists in monkeys All compounds (milligrams per kilogram) were administered intravenously. See Fig. 1 for other details.

MOR Agonist
KOR Agonist
DOR Agonist
Fentanyl
Alfentanil
Remifentanil
U-50488H
SNC80
Minutes after injection 0.018 0.01 0.0032 0.018 0.01 0.0032 0.0056 0.0032 0.001 0.01–0.32 0.01–0.32
0–15 * * * * * * * * * N.S. N.S.
15–30 * * * * * N.S. * N.S. N.S. N.S. N.S.
30–45 * * N.S. * * N.S. N.S. N.S. N.S. N.S. N.S.
45–60
*
*
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.

  • *, p < 0.05; N.S., not significant from vehicle.