Early postischemic 45Ca accumulation in rat dentate hilus.
Several studies have found postischemic regional accumulation of calcium to be time-dependent and coincident with the progression of ischemic cell change. In the most vulnerable cells in the hippocampus one would therefore expect to find a primary and specific early uptake of calcium after ischemia. Autoradiograms of 45Ca and 3H-inulin distribution were investigated before and 1 h after 20 min ischemia in the rat hippocampus. Two different methodological approaches were used for administration of 45Ca: (a) administration via microdialysis probes, (b) intraventricular injection. During control conditions the 45Ca autoradiograms showed variations in distribution volume in accordance with 3H-inulin determination of extracellular space size. One hour after ischemia a massive accumulation of 45Ca was found in the dentate hilus. No change in the distribution pattern of 3H-inulin could be demonstrated 1 h after ischemia. We suggest that 45Ca accumulation in dentate hilus 1 h after ischemia is a result of increased Ca2+ uptake before irreversible cell damage occurs and is not due to passive influx of calcium across a leaky plasma membrane.
Institute of Neuropathology, University of Copenhagen, Denmark.
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Benveniste
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Diemer
D000818:Animals; D001345:Autoradiography; D002545:Brain Ischemia / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D006624:Hippocampus / Q000378:metabolism*; D007444:Inulin / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium
D002132:Calcium Radioisotopes; D014316:Tritium; D007444:Inulin; D002118:Calcium