Annual Meeting of the Society for Neuroscience edition:34 location:San Diego, CA, U.S.A. date:October 23-27, 2004
We examined the expression profile of neurofilament protein in discrete cell types in wholemounts and sections of adult cat retina using a monoclonal antibody (SMI-32), which recognizes the non-phosphorylated epitope on the high molecular weight subunits of neurofilament proteins. A conspicuous pattern of strongly labeled optic nerve fibers displayed the area centralis and raphe. A population of large retinal ganglion cells exhibited neurofilament protein expression in their soma and the proximal parts of the dendritic arbors. These immunopositive cells were equally distributed throughout the retina, but with the lowest density in the central retina. Their immunoreactive dendrites branched into sublamina a of the inner plexiform layer, well described as the OFF inner plexiform sublamina. The ganglion cell layer also contained a uniformly distributed population of smaller somas faintly labeled, which might refer to displaced amacrine cells. In addition, in the outer plexiform layer a mosaic of A-type horizontal dendrites was strongly immunoreactive for neurofilament protein. In conclusion, we propose that the large size and the typical distribution profile of immunopositive cells together with the specific branching pattern of its dendrites indicate that the SMI-32-positive ganglion cells correspond to the functional alfa OFF-ganglion cell population.