Cortical substance P-like immunoreactivity in cases of Alzheimer's disease and senile dementia of the Alzheimer type.

The concentration of substance P-like immunoreactive material (SPLI) and somatostatin-like immunoreactive material (SLI) and the activity of acetyl-CoA: choline-O-acetyltransferase (ChAT; EC 2.3.1.6) were measured in eight brain regions of 13 normal patients and 12 patients with Alzheimer disease/senile dementia of the Alzheimer type (AD/SDAT). SPLI was significantly lower in five of eight regions in the patients with AD/SDAT. Younger patients with AD/SDAT had significantly lower SLI in the parietal cortex than older patients. ChAT activity and SPLI in the parietal cortex of the presenile patients with AD/SDAT were not significantly different from values found in older patients.