The transneuronal transport of proline within the mouse visual system: some characteristics of the [3H]-proline...

Following the intraocular injection of tritiated proline in the mouse, the progressive transport of radioactivity in the brain and the nature of the cortical material(s) to which the label is bound was examined. About 35-40% of the radioactivity that was present in the cerebral cortex at four weeks post-injection was extractable with either distilled water or various buffers. By using 0.1% SDS this value can be increased up to 94%. Polyacrylamide gel electrophoresis of the extracted proteins showed that a major part of the radioactivity is accumulated in one band of proteins. This heavily labeled band could not be identified in the homolateral parietooccipital cortex or in the frontal cortex. Similarly, SDS electrophoresis of the SDS-extracted proteins also demonstrated the presence of a major band of proteins whose molecular weight was estimated at approximately 68,000 daltons. The protein was purified by ammonium sulfate precipitation and DEAE-Sephadex separation.