Neuropeptides and Alzheimer's disease.

Numerous neuropeptides have been isolated from the human brain and postulated as neurotransmitter candidates. Their biochemical characteristics and anatomical distribution have been elucidated in some detail, but their possible physiological and pathophysiological roles, as well as their utility as diagnostic markers in brain disorders, have been more difficult to establish. The concentrations of several neuropeptides have been measured in postmortem human brain studies and in cerebrospinal fluid (CSF) of patients with Alzheimer's disease. Here we critically review these findings with focus on: (1) the relation between brain tissue and CSF neuropeptide alterations; (2) the specificity of neuropeptide alterations in Alzheimer's disease in relation to other degenerative brain diseases; (3) possible functional implications.