In situ hybridization of nucleus basalis neurons shows increased β-amyloid mRNA in Alzheimer disease

To determine which cells within the brain produce β-amyloid mRNA and to assess expression of the β-amyloid gene in Alzheimer disease, we analyzed brain tissue from Alzheimer and control patients by in situ hybridization. Our results demonstrate that β-amyloid mRNA is produced by neurons in the nucleus basalis of Meynert and cerebral cortex and that nucleus basalis perikarya from Alzheimer patients consistently hybridize more β-amyloid probe than those from controls. These observations support the hypothesis that increased expression of the β-amyloid gene plays an important role in the deposition of amyloid in the brains of patients with Alzheimer disease.