Peptides in the neocortex in Alzheimer's disease and ageing

Studies which have examined neuropeptides in Alzheimer's disease (AD) and normal ageing are reviewed. A marked specificity and selectivity is noted: most neuropeptides are normal, and the only two peptides consistently altered are somatostatin (SRIF) and corticotropin releasing hormone (CRH). Binding sites for CRH are increased in number in a reciprocal fashion to the reduction in CRH. These findings (1) provide evidence for selective vulnerability within the cortex in AD, (2) suggest that the primary site of pathology in AD may be cortical, and (3) indicate that the pathological process of AD is distinct from that of normal ageing.