Immunohistochemical localization of EphA5 in the adult human central nervous system

To better understand the functional role of EphA5 in the adult human central nervous system (CNS), we performed an immunohistochemical mapping study. EphA5, like other members of the Elk/Eph family of receptor tyrosine kinases, was widely distributed in CNS neurons. However, the distribution of the neuronal staining was not uniform. The abundance of stained neurons appeared to increase from the forebrain to the hindbrain and spinal cord. Glial and endothelial tissue was unstained. These findings are consistent with the existence of receptor and ligand gradients in different brain regions. The localization of EphA5 to motor and sensory neurons is consistent with a role of EphA5 in neural plasticity, cell-cell recognition, and topographical orientation of neuronal systems.