Figure 1

Time-dependent induction of pERK expression by histamine. (A) Few pERK-positive cells are seen in PBS-injected mice. (B-E) An obvious increase in the number of pERK-positive cells is observed at 2 min post-histamine injection (B, E), peak levels are achieved at 30 min and sustained until 60 min (C, E), and a marked decline is seen at 90 min post-injection (D, E). n = 6 for each time point. DH, dorsal horn; df, dorsal fasciculus; lf, lateral fasciculus. Scale bar, 100 μm.