HARACTERIZATION OF EXTRACELLULAR ACCUMULATION OF Zn URING ISCHEMIA AND REPERFUSION OF HIPPOCAMPUS SLICES N RAT

bstract—The mammalian CNS contains an abundance of helatable zinc that is sequestered in the vesicles of glutaatergic presynaptic terminals and co-released with glutaate. Considerable Zn is also released during cerebral schemia and reperfusion (I/R) although the mechanism of his release has not been elucidated. We report here the real ime observation of increase of the concentration of extracelular Zn ([Zn ]o), accompanied by a rapid increase of inracellular free Zn concentration, in the areas of dentate yrus (DG), CA1 and CA3 in acute rat hippocampus slices uring ischemia simulated by deprivation of oxygen and gluose (OGD) followed by reperfusion with normal artificial erebrospinal fluid. A brief period of OGD caused a sustained ncrease of [Zn ]o. Subsequent reperfusion with oxygenated edium containing glucose resulted in a further increase of Zn ]o. Longer periods of OGD caused greater increases of Zn ]o, and subsequent reperfusion caused still further inreases of [Zn ]o, regardless of OGD duration. The Zn 2