Neurotrophin-3 and TrkC are expressed in the outflow tract of the developing chicken heart.

Transcripts encoding trkC and full-length (catalytic) TrkC receptors were detected in the outflow tract of the chicken heart during early development (stage 17; embryonic day [E] 2.5) before the start of septation. Expression of trkC mRNA persisted through early septation (stage 25, E4.5-E5) but was no longer evident by the end of septation (stage 34, E8). Neurotrophin-3 (NT-3) mRNA was also shown to be present in the outflow tract throughout cardiac development. Quail-chick chimeras were used to confirm that cardiac neural crest cells were not present in the outflow tract at stage 17 (E2.5). Our results show that NT-3 interacts with cells in the outflow tract that are not of neural crest origin. This finding indicates that, in addition to effects on neural crest cells, NT-3 may be important for cardiac development due to its interaction with cells in the outflow tract such as those arising from the secondary heart field.