Neuronal RNA in Pick's and Alzheimer's diseases. Comparison of disease-susceptible and disease-resistant cortical areas.

Comparative neuronal RNA analyses were conducted in disease-prone (frontal association, Brodmann's area 9) vs relatively disease-resistant (primary visual, occipital area 17) cortex of patients with autopsy-proved Pick's disease (PD) and Alzheimer's disease (AD). Azure B-RNA staining and scanning-integrating microdensitometry were used to determine total RNA contents of pyramidal neurons in layers 3 and 5. In both PD and AD (1) significant (15% to 47%) RNA loss was detected in neurons of both cortical areas and layers relative to those of aged, nondemented controls, and (2) RNA loss was not markedly enhanced in the damaged frontal cortex relative to that in the preserved occipital cortex. Neuronal RNA depletion was generally more marked in PD than AD. However, this impairment does not appear to be related to the formation of classic neuropathological abnormalities in either disease.