In:
Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 16, No. 5 ( 1996-09), p. 915-922
Abstract:
Hippocampal CA1 neurons exposed to a nonlethal period (2 min) of ischemia, acquired tolerance to a subsequent lethal 5-min period of ischemia, which usually causes delayed-type neuronal death. Intracelluar Ca 2+ movements before and after the 5 min of forebrain ischemia were evaluated in gerbil hippocampal CA1 pyramidal neurons, had acquired tolerance in comparison with nonischemia-tolerant CA1 neurons. Evaluation was performed by observing the ultrastructural intracellular Ca 2+ distribution and the Ca 2+ adenosine triphosphatase (Ca 2+ -ATPase) activity using electron microscopic cytochemistry. In comparison with nonischemia-tolerant CA1 neurons, mitochondria of ischemia-tolerant CA1 neurons sequestered more Ca 2+ from the cytosomal fraction 15 min after the 5-min period of ischemia, and Ca 2+ deposits in these mitochondria were rapidly decreased. Plasma membrane Ca 2+ -ATPase activities were already significantly elevated before the 5 min of ischemia, and remained at a higher level subsequently compared to nonischemia-tolerant CA1 neurons. Changes in the mitochondrial Ca 2+ distribution and Ca 2+ -ATPase activities in ischemia-tolerant CA1 neurons after the 5-min period of ischemia showed a strong resemblance to those in CA3 neurons, which originally possess resistance to such periods of ischemia. These findings suggest that enhanced or maintained activities of mitochondrial Ca 2+ sequestration and plasma membrane Ca 2+ -ATPase reduced Ca 2+ toxicity following 5-min ischemia in terms of time, resulting in escape from delayed neuronal death.
Type of Medium:
Online Resource
ISSN:
0271-678X
,
1559-7016
DOI:
10.1097/00004647-199609000-00015
Language:
English
Publisher:
SAGE Publications
Publication Date:
1996
detail.hit.zdb_id:
2039456-1
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