Zebrin II distinguishes the ampullary organ receptive map from the tuberous organ receptive maps during development in the teleost electrosensory lateral line lobe.
In weakly electric gymnotiform teleosts, monoclonal antibody anti-zebrin II recognizes developing pyramidal cells in the ampullary organ-receptive medial segment of the medullary electrosensory lateral line lobe (ELL) and in the mechanoreceptive nucleus medialis. Developing pyramidal cells in the remaining three tuberous organ-receptive lateral ELL segments are unreactive. These results suggest that certain biochemical features of the ELL ampullary organ-receptive medial segment are more similar to the nucleus medialis than to the tuberous organ-receptive ELL segments, and support the hypothesis that the ampullary system evolved from mechanosensory precursors.