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. 2017 Jul 18;174(17):2842–2861. doi: 10.1111/bph.13908

Figure 7.

Figure 7

Intra‐NAc administration of SCH23390 or U0126 blocked systemic morphine or local DAMGO‐induced behavioural responses in rats that received lesions of the NAc with 6‐OHDA. (A, B) Intra‐NAc microinjection of SCH23390 or U0126 before challenge injection (Test inj) of morphine blocked the expression of behavioural sensitization to morphine. Rats that received lesions of the NAc with 6‐OHDA were treated with saline (Veh) or morphine (10 mg·kg−1, i.p.). Two days later, these rats either were challenged with morphine (10 mg·kg−1, i.p.) or were intra‐NAc microinjected with SCH23390 (0.1 μg/0.5 μL/side) or U0126 (0.1 μg/0.5 μL/side) 30 min before challenge injection of morphine. (C) Effect of administration of SCH23390 or U0126 before the challenge injection of morphine on behavioural sensitization expression in saline‐treated control mice. Rats were treated with saline; 2 days later, these rats were intra‐NAc microinjected with SCH23390 (0.1 μg/0.5 μL/side) or U0126 (0.1 μg/0.5 μL/side), 30 min later, followed by a challenge injection of morphine (10 mg·kg−1, i.p.). Locomotor responses (distance travelled over a period of 180 min in cm) were measured after the challenge injection of morphine. Values are expressed as the mean ± SEM (n = 7–9). *P < 0.05, significantly different from saline‐treated control group; # P < 0.05, significantly different from test injection of morphine without SCH23390 or U0126. One‐way ANOVA followed by Dunnett's post hoc tests. (D) Intra‐NAc microinjection of SCH23390 suppressed locomotor activity induced by direct administration of DAMGO into the NAc in rats that received lesions of the NAc with 6‐OHDA. DAMGO (0.2 μg/0.5 μL/side) was injected into NAc 10 min after intra‐NAc administration of SCH23390 (0.1 μg/0.5 μL/side) or saline. Locomotor responses (distance travelled over a period of 180 min in cm) were measured after 2 h after DAMGO administration. Values are expressed as the mean ± SEM (n = 8). *P < 0.05, significantly different from saline‐treated control group; # P < 0.05, significantly different from DAMGO‐treated group. One‐way ANOVA followed by Dunnett's post hoc tests. (E) Schematic representation of injection sites in the NAc for rats used in the experiments. (F) Photomicrographs of the tyrosine hydroxylase immunoreactive neurons in the striatum after bilateral intra‐NAc infusion of 6‐OHDA.