PROGRAMMED CELL-DEATH IN NEURONS - FOCUS ON THE PATHWAY OF NERVE GROWTH-FACTOR DEPRIVATION-INDUCED DEATH OF SYMPATHETIC NEURONS

Extensive programmed cell death (PCD) occurs in the developing nervous system. Neuronal death occurs, at least in part, because neurons are produced in excess during development and compete with each other for the limited amounts of the survival-promoting trophic factors secreted by target tissues, Neuronal death is apoptotic and utilizes component s that are conserved in other PCD pathways. In this review, we discuss the mechanism of trophic factor-dependent neuronal cell death by focu sing on the pathway of nerve growth factor (NGF) deprivation-induced s ympathetic neuronal death. We describe the biochemical and genetic eve nts that occur in NGF-deprived sympathetic neurons undergoing PCD. Par ticipation of the Bcl-2 family of proteins and the interleukin-1 beta- converting enzyme family of proteases (caspases) in this and other mod els of neuronal death is also examined. The order and importance of th ese components during NGF deprivation-induced sympathetic neuronal dea th are discussed.