Fig. 3. Time course of gene expression for artemin and glial-derived neurotrophic factor mRNA in skin (A , B ) and muscle (C , D ) following plantar incision. Data are expressed as mean fold change (incision/sham) ± SD. *P < 0.05 versus  sham, n = 4 per group. GDNF = glial-derived neurotrophic factor.