A direct demonstration of the perforant pathway terminal zone in Alzheimer's disease using the monoclonal antibody Alz-50.

The perforant pathway links the entorhinal cortex with the hippocampal formation and provides this structure with its major cortical input. The cells of origin of the perforant pathway are destroyed in Alzheimer's disease (AD) and a marked depletion of glutamate, the putative neurotransmitter in its terminal zone, occurs. We report that the monoclonal antibody Alz-50 recognizes an antigen in the terminal zone of the perforant pathway in AD. This observation provides direct evidence for the involvement of the perforant pathway in AD, and demonstrates that Alz-50 can be used to study neural connectivity in AD brains.