Ethanol-induced apoptotic neurodegeneration in the developing brain.

Abstract

It has been known for three decades that ethanol, the most widely abused drug in the world, has deleterious effects on the developing human brain, but progress has been slow in developing animal models for studying this problem, and the underlying mechanisms have remained elusive. Recently, we have shown that during the synaptogenesis period, also known as the brain growth spurt period, ethanol has the potential to trigger massive neuronal suicide in the in vivo mammalian brain. The brain growth spurt period in humans spans the last trimester of pregnancy and first several years after birth. The NMDA antagonist and GABAmimetic properties of ethanol may be responsible for its apoptogenic action, in that other drugs with either NMDA antagonist or GABAmimetic actions also trigger apoptotic neurodegeneration in the developing brain. Our findings provide a likely explanation for the reduced brain mass and neurobehavioral disturbances associated with the human fetal alcohol syndrome. Furthermore, since NMDA antagonist and GABAmimetic drugs are sometimes abused by pregnant women and also are used as anticonvulsants, sedatives or anesthetics in pediatric medicine, our findings raise several complex drug safety issues. In addition, the observation that ethanol and several other drugs trigger massive neuronal apoptosis in the developing brain provides an unprecedented opportunity to study both neuropathological aspects and molecular mechanisms of apoptotic neurodegeneration in the in vivo mammalian brain.