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. Author manuscript; available in PMC: 2010 Sep 30.
Published in final edited form as: J Neurosci. 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 sub-threshold doses of DAMGO (3 ng) and deltorphin (3 ng) with pre-microinjection (1 hour before) of saline in placebo-treated (n=4 rats) and morphine-treated rats (n=6). D, Behavioral effects of pre-microinjections of 0.2 μg 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 pre-microinjection 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 + 3 ng deltorphin, n=6) in rats treated with twice daily injections of morphine. * and # p<0.05, ** p<0.01.