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A Nuclear Microscopic Study of Elemental Changes in the Rat Hippocampus After Kainate‐Induced Neuronal Injury
Author(s) -
Ong WeiYi,
Ren MinQin,
Makjanić Jagoda,
Lim TitMeng,
Watt Frank
Publication year - 1999
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1999.721574.x
Subject(s) - kainate receptor , calcium , calcium in biology , chemistry , hippocampus , cytosol , intracellular , medicine , neurodegeneration , endocrinology , calpain , biophysics , biology , glutamate receptor , biochemistry , ampa receptor , enzyme , receptor , disease
The effect of intracerebroventricular kainate injection on the elemental composition of the hippocampus was studied in adult Wistar rats, at 1 day and 1, 2, 3, and 4 weeks postinjection, using a nuclear microscope. An increase in calcium concentration was observed on the injected side from 1 day postinjection. The increase peaked at 3 weeks postinjection, reaching a concentration of 18 times normal. Large numbers of glial cells but no neurons were observed in the lesioned CA fields at this time, suggesting that an increased calcium level was present in glial cells. This was confirmed by high‐resolution elemental maps of the lesioned areas, which showed very high intracellular calcium concentrations in almost all glial cells. It is possible that the high intracellular calcium level could activate calcium‐dependent enzymes, including calpain II and cytosolic phospholipase A 2 , shown to be expressed in reactive glial cells after kainate injections. In addition to calcium, an increase in iron content was also observed at the periphery of the glial scar at 4 weeks postinjection. Because free iron could catalyze the formation of free radicals, the late increase in iron content may be related to oxygen radical formation during neurodegeneration.