Reduction of neurotensin immunoreactivity in the amygdala in Alzheimer's disease.

The density of neurotensin immunoreactivity (NT-IR) was dramatically decreased in 6 of 12 amygdaloid nuclear subregions in patients with Alzheimer's disease (AD) compared to age-matched normals. Diminution of NT-IR was most pronounced in amygdaloid regions containing the greatest number of senile plaques. This contrasts to our previous findings of little, if any, loss of substance P or somatostatin immunoreactivity within these same regions. The present findings corroborate biochemical reports of a decrease in NT-IR in the AD amygdala and suggest that this peptide may be selectively affected relative to other neuropeptides.