Regional brain calcium changes in the rat middle cerebral artery occlusion model of ischemia.

Abstract
Entry of Ca ions into ischemic neurons is believed to cause cell damage. Although several investigators have demonstrated changes in extracellular Ca ionic activity consistent with Ca movement into cells, direct and quantitative evidence for Ca entry into ischemic cells is lacking. We used atomic absorption spectroscopy to measure the regional distribution of tissue Ca contents of rat brains sampled at 2, 4, and 24 hours after middle cerebral artery occlusion (MCAo). At 4 hours after MCAo, Ca concentrations increased significantly (p less than 0.005) in the ischemic middle cerebral artery territory, i.e., the pyriform and frontoparietal cortices, but not in the surrounding brain. At 24 hours, Ca concentrations in the pyriform and frontoparietal cortex were respectively 30.79 (+/- 2.90) and 29.19 (+/- 3.28) mumol/g dry tissue wt compared with 11.9 (+/- 1.7) mumol/g in sham-occluded rats. Tissue Ca concentration changes in the parasagittal cortex and basal ganglia adjacent to the infarct site were much smal...