Effects of ketoprofen on control and acid-depressed ICSS. Left and centre panels show drug effects on full ICSS frequency-rate curves when ketoprofen or its vehicle was administered as a pretreatment to acid vehicle (left panel A) or 1.8% lactic acid (centre panel B). Filled points represent frequencies at which ICSS rates after ketoprofen treatment were significantly different from rates after Veh + Veh (A) or Veh + 1.8% LA (B) as determined by a two-way ANOVA followed by a Holm–Sidak post hoc test, p < 0.05. Right panel (C) shows summary ICSS data for drug effects on the total number stimulations delivered across all frequencies per test component when ketoprofen was administered as a pretreatment to acid vehicle (open bars) or 1.8% lactic acid (filled bars). Other details as in Fig. 3. All data show mean ± SEM for five rats. Statistical results for the left and centre panels are as follows: (A) ketoprofen + vehicle: Significant main effect of frequency (F[9,36] = 44.79, p < 0.001) but not treatment (F[1,4] = 0.12, p = 0.74); the interaction was not significant (F[9,36] = 0.79, p = 0.63). (B) ketoprofen + 1.8% LA: Significant main effect of frequency (F[9,36] = 45.63, p < 0.001) and treatment (F[1,4] = 60.63, p = 0.001) and a significant interaction (F[9,36] = 2.82, p < 0.05). *Indicates significantly different from Veh + Veh in the right panels as determined by a paired t-test (p < 0.05).