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 exam ined for the immunocytochemical reactivity to 31 commercial antibodies . Nine showed positive reactivity: vimentin, S-100, caldesmon, calbind in, MAP-1, Map-2, parvalbumin, neurofilament, and GAP-43. The cell typ es examined were: hair cells, support cells, hair cell precursors, eig hth nerve neurons, and neuronal precursors. The pattern of reactivitie s among these cell types lead to the following conclusions. First, hai r cells and eighth nerve neurons have a striking immunocytochemical si milarity. Second, the precursor cells for hair cells and neurons did n ot share immunoreactivity with these mature progeny. Third, the only a ntibody to react with supporting cells also reacted with the prolifera ting precursors that give rise to new hair cells and supporting cells. Taken with other available data, these finding suggest that in the os car ear, hair cell precursors and supporting cells are closely related , if not the same cell type.