IMMUNOCYTOCHEMICAL REACTIVITIES OF PRECURSOR CELLS AND THEIR PROGENY IN THE EAR OF A CICHLID FISH

Cell types in the inner ear of the fish Astronotus ocellatus were examined for the immunocytochemical reactivity to 31 commercial antibodies. Nine showed positive reactivity: vimentin, S-100, caldesmon, calbindin, MAP-1, Map-2, parvalbumin, neurofilament, and GAP-43. The cell types examined were: hair cells, support cells, hair cell precursors, eighth nerve neurons, and neuronal precursors. The pattern of reactivities among these cell types lead to the following conclusions. First, hair cells and eighth nerve neurons have a striking immunocytochemical similarity. Second, the precursor cells for hair cells and neurons did not share immunoreactivity with these mature progeny. Third, the only antibody to react with supporting cells also reacted with the proliferating precursors that give rise to new hair cells and supporting cells. Taken with other available data, these finding suggest that in the oscar ear, hair cell precursors and supporting cells are closely related, if not the same cell type.