Fig. 2.
Protein kinase C (PKC) γ–immunoreactive interneurons are activated and PKCγ phosphorylated during the expression of static mechanical allodynia. (A) Fluorescence images of PKCγ-immunoreactive interneurons (green), extracellular signal–regulated kinase 1/2 phosphorylation (phospho-ERK1/2)-immunoreactive cells (red), and double-labeled neurons (white arrows) in lamina IIi of the medullary dorsal horn. Insets show the dually labeled neuron into the white stippled square. (B) Top, Western blots for phospho-PKCγ and β-actin on total medullary dorsal horn proteins for the four groups of rats as indicated below the bar histogram. Bottom, scatter plot of the quantification of Western blotting. Values in each blot are normalized to β-actin staining and then to that in endolipid-injected and mechanically stimulated (6-g von Frey [vF] filament) rats. Treatments are indicated below the bars: (1) time after intradermal capsaicin at which mechanical stimulation is applied, just before animal death, and (2) 3-min static mechanical stimulation (6-g vF filament) applied 0.5 to 1 cm to the injection site, on the area of secondary hypersensitivity. Data are represented as the mean ± SD, n = 4 per group. ***P < 0.001.