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. Author manuscript; available in PMC: 2017 Sep 1.
Published in final edited form as: Eur J Pain. 2016 Feb 23;20(8):1229–1240. doi: 10.1002/ejp.847

Figure 3.

Figure 3

Effects of the ketamine (A–C) and MK-801 (D–F) on control and acid-depressed ICSS. Left and centre panels show drug effects on full ICSS frequency-rate curves when drugs were administered as a pretreatment to acid vehicle (left panels A, D) or 1.8% lactic acid (centre panels B, E). Abscissae: Frequency of electrical brain stimulation in Hz (log scale). Ordinates: Per cent maximum control rate (%MCR). Filled points represent frequencies at which ICSS rates after test drug treatment were significantly different from rates after treatment with Veh + Veh (A, D) or Veh + 1.8% LA (B, E) as determined by a two-way ANOVA followed by a Holm–Sidak post hoc test, p < 0.05. Right panels (C, F) show summary ICSS data for drug effects on the total number of stimulations delivered across all frequencies per test component when drugs were administered as a pre-treatment to acid vehicle (open bars) or 1.8% lactic acid (filled bars). Abscissae: Drug dose (mg/kg). Ordinates: Per cent baseline stimulations per test component. Upward/downward arrows indicate that the drug dose produced a significant increase/decrease in ICSS for at least one brain stimulation frequency as determined by analysis of full frequency-rate curves in the left and centre panels. All data show mean ± SEM for five rats. Statistical results for the left and centre panels are as follows: (A) ketamine + vehicle: Significant main effect of frequency (F[9,36] = 120.50, p < 0.001) and treatment (F[3,12] = 10.22, p = 0.001) and a significant interaction (F[27,108] = 2.88, p < 0.001). (B) ketamine +1.8% LA: Significant main effect of frequency (F[9,36] = 42.15,p < 0.001) but not dose (F[3,12] = 0.50, p = 0.69); the interaction was not significant (F[27,108] = 0.39, p = 0.99). (D) MK-801 + vehicle: Significant main effect of frequency (F[9,36] = 117.00, p < 0.001) and treatment (F[4,16] = 19.41, p < 0.001) and a significant interaction (F[36,144] = 8.13, p < 0.001). (E) MK-801 +1.8% LA: Significant main effect of frequency (F[9,36] = 57.40, p < 0.001) and dose (F[4,16] = 10.05, p < 0.001) and a significant interaction (F[36,144] = 8.40, p < 0.001). *Indicates significantly different from Veh + Veh in the right panels as determined by a paired t-test (p < 0.05).