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. 2004 Sep 22;24(38):8300–8309. doi: 10.1523/JNEUROSCI.2893-04.2004

Figure 3.

Figure 3.

a-d, PI3K and ERK are required for the induction and expression of capsaicin-induced heat hyperalgesia without affecting basal sensitivity. a, b, Pretreatment, Intradermal injection of PI3K inhibitors (LY294002, 1 and 10 μg; wortmannin, 0.2 μg) or MEK inhibitors (PD98059, 1 and 10 μg; U0126, 1 μg) before capsaicin injection prevents heat hyperalgesia in a dose-dependent manner. *p < 0.01; +p < 0.05, compared with vehicle control (n = 6). c, Posttreatment, Intradermal injection of LY294002 (10 μg) or PD98059 (10 μg), 15 min after capsaicin injection, reverses heat hyperalgesia. *p < 0.01, compared with control (n = 6). d, LY294002 (10 μg) or PD98059 (10 μg) has no effect on basal heat sensitivity (n = 6). p > 0.05. Heat sensitivity was measured by PWL and plotted as a proportion of preinjection baseline. The basal PWL (in seconds) in a, b, c, and d is 15.4 ± 0.6 (n = 24), 16.4 ± 0.5 (n = 24), 14.4 ± 0.5 (n = 18), 17.0 ± 0.8 (n = 12), respectively (mean ± SEM). Cont, Control; Ly, LY294002; PD, PD98059; Wort, wortmannin.