Lumbo-sacral neural crest contributes to the avian enteric nervous system independently of vagal neural crest

Most of the avian enteric nervous system is derived from the vagal neural c rest, but a minority of the neural cells in the hindgut, and to an even les ser extent in the midgut, are of lumbo-sacral crest origin, Since the lumbo -sacral contribution was not detected or deemed negligible in the absence o f vagal cells, it had been hypothesised that lumbo-sacral neural crest cell s require vagal crest cells to contribute to the enteric nervous system. In contrast, zonal aganglionosis, a rare congenital human bower disease led t o the opposite suggestion, that lumbo-sacral cells could compensate for the absence of vagal cells to construct a complete enteric nervous system. To test these notions, we combined E4 chick midgut and hindgut, isolated prior to arrival of neural precursors, with E1.7 chick vagal and/or E2.7 quail l umbo-sacral neural tube as crest donors, and grafted these to the chorio-al lantoic membrane of E9 chick hosts. Double and triple immune-labelling for quail cells (QCPNA), neural crest cells (HNK-1), neurons and neurites (neur ofilament) and glial cells (GFAP) indicated that vagal crest cells produced neurons and glia in large ganglia throughout the entire intestinal tissues . Lumbo-sacral crest contributed small numbers of neurons and glial cells i n the presence or absence of vagal cells, chiefly in colorectum, but not in nearby small intestinal tissue, Thus for production of enteric neural cell s the avian lumbo-sacral neural crest neither requires the vagal neural cre st, nor significantly compensates for its lack. However, enteric neurogenes is of lumbo-sacral cells requires the hindgut microenvironment, whereas tha t of vagal cells is not restricted to a particular intestinal region. (C) 2 000 Wiley-Liss, Inc.