Age-dependence of neuronal apoptosis and of caspase activation

Abstract

A widely accepted morphological classification of cell death divides it into three types: apoptosis, autophagy and necrosis. Research into the biochemical basis of cell death began with apoptosis, and in recent years the programmed mechanisms contributing to cell death and apoptosis became synonymous. This has created confusion, because apoptosis refers to a particular morphology and not to a biochemical pathway. Within the central nervous system, both naturally occurring and pathologically induced neuronal apoptosis occurs during the neonatal period in rodents, and becomes virtually undetectable in adult rodents. In the same way, the caspase-dependent programmed cell death pathways are also most prominent in neonatal rodents, and also disappear in adult rodents, although there are earlier studies to the contrary. In adult rodents, acute neuronal injury induces neuronal necrosis, which involves caspase-independent programmed cell death mechanisms.