Fig. 8.
Schematic representation of the relative timing of Phox2 and DBH expression in the peripheral nervous system.Plus (+) and minus (−)signs refer to Phox2 expression and +/− signs indicate weak levels of expression. Dark shading, light shading, and white backgrounds indicate strong, weak, and undetectable DBH expression, respectively. At all sites, the onset of Phox2 expression is roughly concomitant with that of DBH, and significantly outlasts it in parasympathetic, myenteric, and cranial ganglia. The exact beginning of Phox2 and DBH expression in the gut is difficult to assess because of the rostrocaudal progression of the signal, and it was not investigated in detail. Postnatal expression of Phox2 in the gut and cranial ganglia was not determined (nd).