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. 2017 Jul;362(1):14–23. doi: 10.1124/jpet.117.240796

Fig. 2.

Fig. 2.

Effects of methylphenidate on acid-induced depression of ICSS in the absence or presence of dopamine receptor antagonists. (A) Full frequency-rate curves. Abscissae: frequency of electrical brain stimulation in Hertz (log scale). Ordinates: % MCR. Filled symbols show significant differences from vehicle plus 1.8% lactic acid (Veh + LA) as determined by repeated-measures two-way ANOVA followed by the Holm-Sidak post-hoc test (P < 0.05). (B) Summary measure of baseline stimulations per component. Abscissae: dose in mg/kg (log scale). Ordinates: percent baseline stimulation per component. Asterisks show significant difference compared with vehicle plus 1.8% lactic acid following a repeated-measures one-way ANOVA followed by Dunnett’s post-hoc test (*P < 0.05; **P < 0.01). (C and D) Effects of the D1 antagonist SCH39166 (SCH) or the D2/3 antagonist eticlopride (Etic) on methylphenidate antinociception. Abscissae: dose of methylphenidate in mg/kg. Ordinates: percent baseline stimulations per component. (C) $Significant difference between effects of Veh + Veh and Veh + 0.32 mg/kg methylphenidate; *Significant difference between Veh + 0.32 mg/kg methylphenidate and 0.01 mg/kg SCH39166 + 0.32 mg/kg methylphenidate, as determined by repeated-measures two-way ANOVA followed by the Holm-Sidak post-hoc test (P < 0.05). (D) #Significant main effect of methylphenidate dose as determined by two-way ANOVA. Data presented are the mean ± S.E.M. of five rats, and identical data are used for antagonist vehicle in (C) and (D) because both drugs used the same vehicle. Statistical results are as follows. (A) Significant main effects of frequency [F(9,36) = 176.4, P < 0.0001] and dose [F(4, 16) = 13.2, P < 0.0001] and a significant interaction [F(36, 144) = 4.0, P < 0.0001]. (B) Significant effect of dose [F(1.8, 7.2) = 12.7, P < 0.01)]. (C) Significant main effects of methylphenidate dose [F(1,4) = 11.31, P < 0.05] and SCH39166 dose [F(1,4) = 41.88, P < 0.01] and a significant interaction [F(1,4) = 9.750, P < 0.05]. (D) Significant main effects of methylphenidate dose [F(1,4) = 14.55, P < 0.05] and eticlopride dose [F(1,4) = 10.96, P < 0.05], but the interaction was not significant [F(1,4) = 1.162, P = 0.27].