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. 2010 Mar 31;30(13):4735–4745. doi: 10.1523/JNEUROSCI.5968-09.2010

Figure 7.

Figure 7.

Mixture of MOR and DOR agonists produces behavioral synergism. A, Effects of a single microinjection (arrow) of saline (n = 4 rats), DAMGO (10 ng, n = 5), or deltorphin (1 μg, n = 5) into the brainstem NRM on pain threshold measured by the tail-flick test in morphine-treated rats in vivo. B, Dose-dependent effects of microinjected DAMGO and deltorphin on the pain threshold in morphine-treated rats. n = 4–6 rats. C, Behavioral effects of NRM-microinjected 1:1 mixture composed of subthreshold doses of DAMGO (3 ng) and deltorphin (3 ng) with premicroinjection (1 h before) of saline in placebo-treated (n = 4 rats) and morphine-treated rats (n = 6). D, Behavioral effects of premicroinjections of 0.2 and 2 μg AACOCF3 on the mixture-induced antinociception in morphine-treated rats. n = 6 rats for each group. E, Behavioral effects on pain threshold produced by NRM microinjections of 6 ng DAMGO and by the mixture (6 ng at 1:1 ratio) with premicroinjection of saline or AACOCF3 (0.2 μg and 0.2 μg). F, Behavioral effects of NRM microinjection of saline (n = 4 rats), deltorphin (3 ng, n = 4), DAMGO (6 ng, n = 5), and the mixture (3 ng DAMGO plus 3 ng deltorphin, n = 6) in rats treated with twice daily injections of morphine. * and # p < 0.05, **p < 0.01.