The development of neurotrophin receptor Trk immunoreactivity in the retina of the zebrafish (Brachydanio rerio).
The purpose of this study was to examine the cellular distribution of the Trk family of neurotrophin receptors in the retina and optic nerve of the zebrafish (Brachydanio rerio) during embryonic development. Semithin sections from zebrafish retinae were examined immunohistochemically for the presence of Trk polypeptides using commercially available antisera that cross-react with the fish. Cross-reactivity was confirmed by Western blot. Trk polypeptides were detected at about 1 day of age on the surfaces of retinal neuroblasts and faint Trk immunoreactivity was observed in the primordial optic nerve at 1.5 days. By 2 days the optic nerve was clearly positive for Trk and at 2.5 days Trk immunoreactivity was found in the outer plexiform, inner nuclear, inner plexiform and ganglion cell layers, as well as in the optic nerve. At 3 days and 4 days the location of Trk immunoreactivity was unchanged but by 4 days it had diminished in intensity. In the adult zebrafish retina Trk immunoreactivity was found in the same locations as in the embryonic fish, as well as in a population of cells in the middle of the inner nuclear layer and in photoreceptors. We conclude that Trk neurotrophin receptors are present in the zebrafish eye during development and that their persistence in the adult may support the continuous neural reorganization that accompanies the growth of the eye in the fish.
Sandell
J H
JH
Department of Anatomy and Neurobiology, Boston University School of Medicine, MA 02118.
Martin
S C
SC
Heinrich
G
G
D000818:Animals; D015153:Blotting, Western; D003429:Cross Reactions; D007150:Immunohistochemistry; D011233:Precipitin Tests; D017475:Receptors, Nerve Growth Factor / Q000032:analysis*; D012160:Retina / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D012995:Solubility; D015027:Zebrafish / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*
D017475:Receptors, Nerve Growth Factor