Fig. 3.
Effects of intramuscular (IM) or subcutaneous (SQ) injection of 30 mM H2O2 on conditioned place aversion (CPA) in rats. Each column represents the time spent in the preferred and nonpreferred chambers during the preconditioning and postconditioning sessions (A) and the CPA scores (B) of the intramuscular injection of the synthetic interstitial fluid (SIF) group (n = 8), subcutaneous injections of the H2O2 (30 mM, 0.6 ml) group (n = 8), and intramuscular injection of the H2O2 (30 mM, 0.6 ml) group (n = 8), intramuscular sequential injection of AP-18 (50 mM, 0.3 ml), followed by the H2O2 (60 mM, 0.3 ml) group (n = 9). All of the data are expressed as mean ± SD. *P = 0.0011 by paired t test. †P = 0.0036 compared with the SIF group, ‡P = 0.0026 compared with the subcutaneous injection of H2O2 group, #P = 0.0048 compared with the intramuscular coinjection of H2O2 and AP-18 group by one-way ANOVA (F3, 29 = 7.212, P = 0.0009) followed by post hoc Tukey test.