Table 1
The antinociceptive effect of DPDPE and DAMGO at spinal level in naive and morphine-tolerant mice
Pretreatment
AD
50
of peptides (95% confidence limits)
DPDPE
DAMGO
nmol/mouse
Naive
5.8 (3.7–8.9)
0.06 (0.04–0.09)
Morphine pellet
22 (15–32)
0.11 (0.07–0.18)