Representative images showing low (left panels) and high (right panel) power views of calcitonin-gene-related peptide (CGRP) immunoreactivity in the DRG at gestational ages as indicated on the left. In the DRG in 4- and 5-gestational month-old fetuses (A–D), a diffuse and weak CGRP labeling is present in the perikarya of many DRG neurons. In 7- and 8-gestational month-old samples, a subset of DRG neurons are strongly labeled, while some other neurons are weakly labeled (E–H). No immunoreactivity is seen in the nucleus. Scale bar = 80 μm in A, C and 20 μm in B, D