Table 7

The synergistic effect between DAMGO and DPDPE in morphine-tolerant mice when administered with i.t. at different ratios

Ratios DAMGO/DPDPEAD50 Values of Peptides (95% confidence limits)
DAMGODPDPE
nmol/mouse
1:500.1  (0.07–0.19)5.6  (3.3–9.5)
1:1000.07  (0.04–0.12)7.2  (4.3–12.1)
1:2000.05  (0.04–0.07)9.7  (7.1–13.3)
1:5000.04  (0.03–0.06)20.0  (14.0–28.5)