Time course of licking responses in PND22 male (A) and female (B) rats in response to an injection of 0.9%, 1%, and 1.1% formalin into the plantar surface of the left hindpaw.

<p>Data are presented as mean +/− SE. * <i>p</i><.05; **<i>p</i><.01, against other groups at the same time point.</p

Time course of flinching responses in PND13 rats (males and females combined) in response to an injection of 0.6%, 0.7%, and 0.8% formalin into the plantar surface of the right hindpaw.

<p>Data are presented as mean +/− SE. * <i>p</i><.05; **<i>p</i><.01, *** <i>p</i><.001, against other groups at the same time point.</p

Time course of flinching responses in PND82 rats (males and females combined) in response to an injection of 1.25%, 1.75%, and 2.25% formalin into the plantar surface of the right hindpaw.

<p>Data are presented as mean +/− SE. * <i>p</i><.05, against other groups at the same time point.</p

Time course of licking responses in PND7 rats (males and females combined) in response to an injection of 0.3%, 0.4%, and 0.5% formalin into plantar surface of the left hindpaw.

<p>Data are presented as mean +/− SE. * <i>p</i><.05; **<i>p</i><.01; *** <i>p</i><.001, against other groups at the same time point.</p

Time course of licking responses in PND82 male (A) and female (B) rats in response to an injection of 1.25%, 1.75%, and 2.25% formalin into the plantar surface of the right hindpaw.

<p>Baseline is the time prior to formalin injection (10 min). Data are presented as mean +/− SE. * <i>p</i><.05, **<i>p</i><.01, against other groups at the same time point.</p

Fos immunoreactivity in the habenula following a neonatal immune challenge and subsequent inflammatory pain.

<p>(A) Representative examples illustrate the distribution of Fos-positive nuclei in the lateral and medial habenula (LHb & MHb, respectively). (B) Quantification of Fos-positive nuclei in LHb and MHb in neonatal saline (white bar) and LPS-treated rats (grey bar) after formalin injection in preadolescent rats. 3V: third ventricle. ***<i>p</i><.001. Scale bar = 100 µm for the 10x microscopic objective and 200 µm for 20x microscopic objective.</p

Neonatal LPS exposure enhances formalin-induced nociception in preadolescent rats.

<p>Time course of flinching (A) and licking (B) responses following an injection of 1.1% formalin (mean ± SEM). AUC: the Area Under the Curve.</p

Fos immunoreactivity in the midbrain periaqueductal grey (PAG) following a neonatal immune challenge and subsequent inflammatory pain.

<p>Representative examples illustrate the distribution of Fos-positive nuclei in the dorsal and ventrolateral PAG (DPAG, VLPAG, respectively) at the rostral (A & B) and caudal (C & D) axes following formalin injection in preadolescent rats. (E) Quantification of Fos-positive nuclei in DPAG between neonatal saline and LPS-treated rats. (F) Quantification of Fos-positive nuclei in lateral PAG (LPAG). (G) Quantification of Fos-positive nuclei in VLPAG. Data are presented as mean ± SEM. *<i>p</i><.05; **<i>p</i><.01. Scale bar = 100 µm.</p