A new cat Fos antibody to localize the immediate early gene c-fos in mammalian visual cortex after sensory stimulation

We developed a novel antibody against cat Fos by immunizing rabbits with a 26-amino-acid peptide. Immunocytochemistry on visual cortex of cats undergo ing different visual manipulations was applied to test the reliability and the efficacy of this antiserum. One hour of light stimulation after an over night dark adaptation resulted in strongly induced Fos expression in supra- and infragranular layers of cat primary visual cortex. Shortterm monocular deprivation changed the Fos expression profile into a columnar immunostain ing related to ocular dominance columns. Fos expression has also been analy zed in cats in which visual input was confined to the right hemisphere by s ectioning the left optic tract and the corpus callosum. In the right hemisp here, visual stimulation elicited Fos induction, whereas in the contralater al hemisphere a very low Fos signal was observed. The specificity of this n ewly synthesized antibody was confirmed by Western blotting. To further est ablish the applicability of this Fos antiserum, we performed immunostaining on monkey and rat visual cortex. This new cat Fos antibody appears to be e xcellent for study of Fos expression as a marker for mapping neuronal activ ity in mammalian brain.