Brain anaerobic lactate production: a suicide note or a survival kit?

Aerobic energy metabolism utilizes glucose and oxygen to satisfy all the energy needs of the adult brain. Anaerobically, the brain switches to the significantly less efficient glycolytic pathway for its most basic energy requirements. Anaerobic glycolysis provides the adult brain with a limited amount of energy and time to maintain ion homoeostasis and other essential processes before several events occur that lead to brain cell damage and death. Recent evidence that lactate, produced mainly in glial cells during a period of oxygen deprivation, becomes the only utilizable and thus obligatory substrate for aerobic energy metabolism upon reoxygenation is summarized here. This evidence also supports the hypothesis that a lactate shuttle exists between glia and neurons, and emphasizes its importance in the post-ischemic survival of neurons.