Figure 3.

In situ hybridization showing PAC₁ receptor (A, C, E, G, I, and K) and PACAP (B, D, F, H, J, and L) gene expression in transverse sections of E10.5 (30–35 somite) mouse embryos. Sections shown are hindbrain (A–D), midbrain (E–H), and spinal cord (I–L). ³³P-labeled antisense riboprobes were synthesized from rat (receptor) and mouse (ligand) cDNA templates. Upper are bright field (silver grains are black), and Lower are the same section in dark field (silver grains appear white). Arrow in B marks the approximate position of the alar/basal boundary. No significant hybridization signals were seen with sense probes.