Alzheimer's, ageing and amyloid: an absurd allegory?

Recent research into the pathogenesis of Alzheimer's disease (AD) has focused upon the proposed neurotoxic role played by the beta-amyloid peptide. Other important neurochemical disturbances, such as the dramatic breakdown of intracellular signalling, should however not be overlooked. In the present article, the authors attempt to investigate the relationship between signalling disturbances and beta-amyloid and ask the question 'which came first?' The available evidence is discussed, and it is concluded that the need for a wide, rather than restricted, focus on biochemical events associated with AD is required if progress is to be made in the understanding and eventual treatment of this disease.