Ror2 and Ryk contribute to spine plasticity in spinal neurons in chronic pain models. A, C, Quantification of synaptic spine density in spinal dorsal horn neurons in vivo 24 h after the injection of CFA (A) or 7 d after SNI nerve lesion (C) in the presence or absence of intrathecal administration of a siRNA against Ror2 or Ryk. B, D, Examples of high-magnification views of microscopic images of labeled dendrites with synaptic spines are shown for the groups represented in A and C. N = 3–4 animals/condition, 20–30 neurons, 500–700 spines counted and analyzed. Two-way ANOVA for random measurements, followed by Bonferroni's test, were performed. *p < 0.05 compared with control group (vehicle or sham treated); †p < 0.05 compared with the group that received only the nociceptive stimuli but not the inhibitor. In all panels, data are represented as the mean ± SEM. Scale bars: B, D, 10 μm.