Brain-derived neurotrophic factor in the control human brain, and in Alzheimer's disease and Parkinson's disease

Brain-derived neurotrophic factor (BDNF) is a small dimeric protein, struct urally related to nerve growth factor, which is abundantly and widely expre ssed in the adult mammalian brain. BDNF has been found to promote survival of all major neuronal types affected in Alzheimer's disease and Parkinson's disease, like hippocampal and neocortical neurons, cholinergic septal and basal forebrain neurons, and nigral dopaminergic neurons. In this article, we summarize recent work on the molecular and cellular biology of BDNF, inc luding current ideas about its intracellular trafficking, regulated synthes is and release, and actions at the synaptic level, which have considerably expanded our conception of BDNF actions in the central nervous system. But our primary aim is to review the literature regarding BDNF distribution in the human brain, and the modifications of BDNF expression which occur in th e brain of individuals with Alzheimer's disease and Parkinson's disease. Ou r knowledge concerning BDNF actions on the neuronal populations affected in these pathological states is also reviewed, with an aim at understanding i ts pathogenic and pathophysiological relevance. (C) 2000 Elsevier Science L td. All rights reserved.