After many years of neglect, the study of normal cell death and the so-called programmed cell death has finally gained some needed momentum. Evidence obtained over the last five years indicates that programmed cell death (also referred to as apop tosis) occurs normally in most animal tissues at some we- defined stages of their development and/or maturation. The molecular mechanisms by which it is executed remains - known. However, key regulatory and metabolic steps have been identified in the apoptotic cascade and a central concept has progressively emerged: Apoptosis appears to occur by default in many different cell types unless suppressed by signals ori- nating from neighboring cells. As Martin Raff noted a few years ago, this molecular cascade probably imposes a form of social control on cell survival and cell death. Since our understanding of the apoptosis phenomena has grown significantly over the last few years, we have been - powered by recent technological advances to biochemically d- sect the key metabolic components of apoptotic and necrotic cascades in normal and injured brains. Moreover, the devel- ment of improved histochemical tools has allowed us to better define the fundamental criteria of cell death, and transgenic te- nology has allowed scientists to test working hypotheses p- taining to the mechanism of action of the so-called “cell death gene.
