In vitro ischemia-induced intracellular Ca2+ elevation in cerebellar slices: a comparative study with the values found in hippocampal slices.
Changes in levels of intracellular calcium ion ([Ca2+]i) induced by in vitro ischemic conditions in gerbil cerebellar and hippocampal slices were investigated using a calcium imaging system and electron microscopy. When the cerebellar slice was perfused with a glucose-free physiological medium equilibrated with a 95% N2/5% CO2 gas mixture (in vitro ischemic medium), a large [Ca2+]i elevation was region-specifically induced in the molecular layer of the cerebellar cortex (a dendritic field of Purkinje cells). When the hippocampal slice was perfused with in vitro ischemic medium, a large [Ca2+]i elevation was region-specifically induced in CA1 field of the hippocampal slices. Electron microscopic examinations showed that the large [Ca2+]i elevations occurred in Purkinje cells and CA1 pyramidal neurons. To isolate Ca2+ release from intracellular Ca2+ store sites, the slices were perfused with Ca(2+)-free in vitro ischemic medium. The increases in [Ca2+]i in both cerebellar and hippocampal slices were significantly lower than those observed in the slices perfused with the Ca(2+)-containing in vitro ischemic medium. However, the suppression of the [Ca2+]i elevation in the molecular layer of the cerebellar slices was smaller than that in the CA1 field of the hippocampal slices. These results reinforce the hypothesis that calcium plays a pivotal role in the development of ischemia-induced neuronal death, and suggest that Ca2+ release from intracellular Ca2+ store sites may play an important role in the ischemia-induced [Ca2+]i elevation in Purkinje cells.
Mitani
A
A
Department of Physiology, Ehime University School of Medicine, Japan.
Yanase
H
H
Namba
S
S
Shudo
M
M
Kataoka
K
K
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000032:analysis*; D002531:Cerebellum / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D005849:Gerbillinae; D006624:Hippocampus / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D066298:In Vitro Techniques; D008297:Male; D011689:Purkinje Cells / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000648:ultrastructure*
D002118:Calcium