Content area
Abstract
Temporal lobe epilepsy is often accompanied by hippocampal sclerosis, a severe and selective loss of a subset of hippocampal neurons. Mossy fibers contain an unusually high concentration of zinc and innervate regions of the hippocampas that contain neurons showing selective vulnerability. We investigated the role of zinc in neurodegeneration and protection following epileptic seizures. We found that CA3 interneurons accumulated high concentrations of zinc and died, whereas CA3 pyramidal cell accumulated moderate amount of zinc and survived. High concentrations of intracellular zinc are observed only in interneurons that are sensitive to neurotrauma. However, low concentration of intracellular zinc in pyramidal cells activates (the serin-threonine kinase) Akt, thus providing protection against neurodegeneration. This dual action of zinc seems to explain the selective pattern of cell death in hippocampal sclerosis.
