Inhibition of EDNRB signaling primarily affects the speed of ENCC migration. A, B. The speed and angle of migration (mean ± s.e.m.) of tracked control ENCCs (these are the same data as shown in Figure 1) and ENCCs in explants exposed to the EDNRB antagonist, BQ-788 (20 μM). A. ENCC speed in explants exposed to BQ-788 is significantly lower than in control explants, except for ENCCs that were 150 to 300 μm from the migratory wavefront (t tests). B. The angle of migration between the locations at the beginning and end of imaging for each ENCC, relative to the long axis of the gut. Only angles between 0° and 180° were used. The angles of ENCCs exposed to BQ-788 were not significantly different from controls except for ENCCs that were 600 to 750 μm from the wavefront, where BQ-788-treated ENCCs migrated at a higher angle than control ENCCs. C. E12.5 colon explant exposed to BQ-788. The growth cone (arrows) of a neurite is in advance of the most caudal ENCC cell body. An ENCC cell body (asterisk) uses the neurite as a substrate. EDNRB, endothelin receptor type B; ENCCs, enteric neural crest-derived cells.