Figure 2

SCDH atypical PKC expression, and effects of PKMζ/PKC inhibition on capsaicin-induced allodynia. (a) Western blots and (b) histograms (% change) of atypical PKC showing i.pl. capsaicin increased PKMζ, but not PKCζ or PKCι/λ, in SCDH from 2-24 h (*P < 0.05, n = 7/12 vehicle/capsaicin). c) Primary/secondary allodynia test sites in capsaicin-injected rats. d) Paw-withdrawal thresholds (PWTs) 24 h post-capsaicin after anesthesia (n = 5) or no-anesthesia (n = 5) of the primary site. Primary, but not secondary, allodynia was attenuated by anesthesia (*P < 0.05, from no-anesthesia). (e,f) Pre- and post-capsaicin PWTs (g) with ZIP, scr-ZIP, NPC-15437 or vehicle (n = 15,4,6,6, respectively) given 24 h post-capsaicin. ZIP (*P < 0.05), but neither scr-ZIP nor NPC-15437, significantly reversed capsaicin-induced allodynia 40-120 min post-drug. (g,h) Effect of ZIP given 20 min before testing on paw-withdrawal latencies, PWLs (s) and PWTs (g) 24 h after capsaicin or vehicle (n = 6,4, respectively). g) Heat hyperalgesia present at 2 h post-capsaicin (*P < 0.05, from vehicle), abated by 24 h, and PWLs were unaffected by ZIP. h) Mechanical allodynia 24 h post-capsaicin (*P < 0.05 from vehicle) was reversed by ZIP. (i,j) Effect of ZIP or scr-ZIP (n = 11, 8, respectively) 100 min post-capsaicin on PWLs and PWTs 20 min, 2 and 24 h post-capsaicin. i) Heat hyperalgesia (20 min-2 h, †P < 0.05 from baseline), abated by 24 h, and was unaffected by ZIP at 2-24 h post-capsaicin. j) Mechanical allodynia was significantly attenuated at 2 h, and reversed at 24 h, post-capsaicin by ZIP (*P < 0.05 from scr-ZIP).