Living with the enemy: a physiological role for the beta-amyloid peptide

The Abeta peptide, which is derived from the processing of the amyloid precursor protein APP, is the principal agent responsible for the pathogenesis of Alzheimer's disease. In a recent study by Kamenetz et al., Abeta is shown to mediate a physiological homeostatic mechanism that reduces excitatory transmission in response to neuronal activity. Failure of this autoregulatory feedback could lead to the neuropathology of Alzheimer's disease.