Figure 8.
ENCDC precursor late-born enteric neurons express many subtypes of 5-HT receptor and SERT; myenteric dopaminergic neurons do not express SERT but are surrounded by a ring of SERT-immunoreactive (putatively serotonergic) terminal axons. A, Immunoselection with antibodies to p75NTR was used to isolate from the fetal intestine at E16. RT-PCR was used to determine whether these cells express transcripts encoding 15 subtypes, encompassing each of the families of 5-HT receptor. The brain was investigated as a positive control. In addition to p75NTR, both brain and ENCDCs contained transcripts encoding SERT, 5-HT1A, 5-HT1B, 15-HT1D, 5-HT1F, 5-HT2A, 5-HT2B, 5-HT3A, 5-HT4A, 5-HT4B, 5-HT4E, 5-HT4F, 5-HT5A, 5-HT5B, 5-HT6, and 5-HT7 receptors. B–D, TH and SERT immunoreactivities were demonstrated simultaneously in whole mounts of LMMP from adult mouse ileum. The location, in each panel of a TH-immunoreactive nerve cell body, is shown by an arrow, the location of the ring of SERT-immunoreactive terminal axons by arrowheads, and a SERT-immunoreactive nerve cell body by an arrow with an asterisk. B, TH immunoreactivity. C, SERT immunoreactivity. D, Merged image. Scale bar, 50 μm.