Role of Ca2+ in Ischemic Injury of CNS White Matter

Abstract

Despite the clinical importance, little is known about the mechanisms of ischemic injury inwhite matter. Studies over the past few years showed that early anoxic injury in white matter depends on the presence of extracellular Ca2+ and myelination. An increase in [Na+]i due to anoxic depolarization causes reverse operation of the Na+-Ca2+ exchanger, which mediates Ca2+ influx during anoxia. The resistance of premyelinated and amyelinated axons to anoxic injury suppoıts the hypothesis that Ca2+ influx occurs at nodes of Ranvier in axons. it is not known what cascades of events are triggered by Ca2+ influx in white matter, and whether anoxia induces increases in intracellular Ca2+ in also glial cells.