Identified taste bud cell proliferation in the perihatching chick [published erratum appears in Chem Senses 1998 Aug;23(4):459]

Developing taste buds in the anterior mandibular floor of perihatchingchicks were studied by high voltage electron microscopic autoradiography inorder to identify proliferating gemmal cell types. Montaged profiles of 29taste buds in five cases euthanized between embryonic day 21 andposthatching day 2 were analyzed after a single [3H]thymidine injectionadministered on embryonic day 16, 17 or 18. Results showed that dark cellscomprised 55% of identified (n = 900 cells) and 62% of labeled (n = 568cells) gemmal cells as compared with light, intermediate, basal orperigemmal bud cells. Dark cells had both a greater (P < 0.05) number oflabeled cells and a greater amount of label (grains/nucleus) than the otherfour bud cell types, irrespective of injection day. The nuclear area(micron 2) of dark cells was not significantly larger (P > 0.05) thanthat of the other gemmal cell types and therefore cannot account for thegreater amount for label in the dark cells. Interestingly, only dark cellsshowed a positive correlation (P < 0.003) between amount of label andnuclear area. Results suggest that, during the perihatching period ofrobust cell proliferation, dividing dark cells may give rise primarily, butnot exclusively, to dark cell progeny.