Figure 1

Single and repeated injections of NAC cause analgesia in the phase II of the formalin test. Nocifensive behavior of mice treated i.p. with a single injection of NAC (100 mg/kg) or saline preceded, 15 min earlier, by saline, sulphasalazine (8 mg/kg), or LY341495 (1 mg/kg) is shown in (A). Values are means ± SEM of 5–12 mice per group. p < 0.05 vs. all other groups of phase II (One-way ANOVA + Holm-Sidak’s test). Nocifensive behavior of mGlu2^−/− or mGlu3^−/− mice and their wild-type littermates treated i.p. with a single injection of NAC (100 mg/kg) or saline is shown in (B) and (C), respectively. Values are means ± SEM of 5 mice per group. p < 0.05 (Two-way ANOVA + Holm-Sidak’s test) vs. wild-type mice injected with saline alone (#) or vs. the corresponding groups of wild-type mice (*). Nocifensive behavior of normal mice treated i.p. with repeated injections of NAC (100 mg/kg) or saline, once a day for 7 days, is shown in (D). Values are means ± SEM of 6 mice per group. *p < 0.05 (Student’s t test) vs. phase II values of mice treated with saline. Motor performance of mice treated with single or repeated injections of NAC or saline on the accelerating rotarod is shown in (E). Values are means ± S.E.M. of 5 mice per group.