Fig. 5. Vagal-to-sacral heterotopic graft, E10. (A) In the colorectum, the myenteric (mp) and submucosal (smp) plexuses contained numerous QCPN+ cells. The nerve of Remak (R) appeared to be poorly developed in transverse sections. (B) Higher magnification revealed that the vast majority of plexus cells were QCPN+, with only a few exceptions in the submucosal plexus (arrowheads).(C) In the post-umbilical intestine, QCPN+ cells were mainly situated external to the circular muscle layers (arrowheads). (A',B',C') In control gut at E10, only very occasional sacral-derived cells were present with the myenteric and submucosal plexuses of the colorectum (B, arrowheads). No immunopositive cells were present in the post-umbilical intestine at this stage of development. Scale bars: 200 µm in A,A'; 50 µm in B,B'; 100 µm in C,C'.