Immunocytochemical localization of the precursor protein for beta-amyloid in the rat central nervous system.

Two rabbit polyclonal antibodies generated against different portions of the amyloid precursor protein were used to localize this protein in normal rat brain. Light and electron microscopic immunohistochemical localizations demonstrate that the protein is widely distributed throughout the neuraxis, with the highest concentrations of immunoreactive neurons occurring in the olfactory bulb, cerebral cortex, septum-diagonal band, globus pallidus, cerebellum, and hippocampus. Immunoreactive astrocytes are also present in the cerebral cortex in relation to both neurons and capillaries. However, immunoreactivity was not observed within the endothelium of the cerebral vasculature. These data demonstrate that the beta-amyloid precursor is widely distributed in the CNS and provide further insight into the cellular elements that may be involved in the neuropathological changes associated with Alzheimer's disease.