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. Author manuscript; available in PMC: 2014 Mar 1.
Published in final edited form as: J Pain. 2013 Jan 16;14(3):246–259. doi: 10.1016/j.jpain.2012.11.006

Figure 3. Acid-induced depression of ICSS.

Figure 3

Left panel (A) compares effects of pretreatment with Vehicle + Vehicle (Veh-Veh) and Vehicle + 1.8% lactic acid (Veh−1.8% LA) on full frequency-rate curves for all 52 rats used in ICSS experiments. Abscissa: Frequency of electrical brain stimulation in log Hz. Ordinate: Percent maximum control response rate (%MCR). Filled symbols indicate a significant difference from Veh-Veh (Holm-Sidak post hoc test, p<0.05). Right panel (B) shows summary data for lactic acid effects on the total number of stimulations per component. Abscissa: Pretreatment conditions. Ordinate: Percent baseline number of stimulations per component. The downward arrow indicates that lactic acid produced a significant decrease in ICSS at one or more frequencies in the full frequency-rate curve. Statistical results for two-way ANOVA of full frequency-rate curves are as follows: (A) Significant main effect of frequency [F(9,459)= 262.185, p<0.001] and treatment [F(1,51)= 202.572, p<0.001]; the interaction was also significant [F(9,459)=16.553, p<0.001].