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Quelle: Gorji 2001 Seite(n): 43, Zeilen: right col. 11ff |
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| The damage to cerebral tissue depends on a complex series of physiological responses and degradative cellular cascades involving a dynamic interplay among the various cells in the region of damaged tissue. Experimental studies of focal ischemic stroke in animals and human support the concept that there is a core of severe ischemia, the ‘ischemic core’ which is surrounded by a region of reduced perfusion, the ‘ischemic penumbra’. Within the ischemic core, failure of oxygen and glucose delivery leads to rapid depletion of energy stores and cell death. Central to the hypothesis of neuronal salvage is the concept of the ischemic penumbra. The penumbra is an area which metabolic capacity is suppressed but destruction is not yet inevitable (Olesen et al., 1986). The etiology of progressive cell injury and death in the penumbra zone has been clarified in some extent. Evidence suggests that SD plays a role in the ischemia–infarction tissue damage process. Excitotoxicity results from excessive release and impaired uptake of excitatory neurotransmitter glutamate. It is hypothesized that excessive amount of glutamate increases intracellular calcium preferentially via NMDA-receptor-mediated channels. A profound increase in extracellular potassium occurs in the ischemic core.
Olesen J (1986) Regional cerebral blood flow (rCBF) studies in migraine and epilepsy. Funct Neurol 1(4):369-74. |
The damage to cerebral tissue depends on a complex series of physiological responses and degradative cellular cascades involving a dynamic interplay among the various cells in the region of damaged tissue. Experimental studies of focal ischemic stroke in animals and human support the concept that there is a core of severe ischemia, the ‘ischemic core’, that is surrounded by a region of reduced perfusion, the ‘ischemic penumbra’. Within the ischemic core, failure of oxygen and glucose delivery leads to rapid depletion of energy stores and cell death. Central to the hypothesis of neuronal salvage is the concept of the ischemic penumbra. The penumbra is an area which metabolic capacity is suppressed but destruction is not yet inevitable [13,322]. The etiology of progressive cell injury and death in the penumbra zone has been clarified in some extent. Evidence suggests that SD plays a role in the ischemia–infarction tissue damage process. Excitotoxicity results from excessive release and impaired uptake of excitatory neurotransmitter glutamate. It is hypothesized that excessive amount of glutamate increases intracellular calcium preferentially via NMDA-receptor-mediated channels. A profound increase in extracellular potassium occurs in the ischemic core.
[13] J. Astrup, L. Symon, N.M. Branston, N.A. Lassen, Cortical evoked potential and extracellular K+ and H+ at critical levels of brain ischemia, Stroke 8 (1) (1977) 51-57. [321] J. Olesen, Regional cerebral blood flow (rCBF) studies in migraine and epilepsy, Funct. Neurol. 1 (1986) 369-374. [322] T.S. Olsen, Regional cerebral blood flow after occlusion of the middle cerebral artery, Acta Neurol. Scand. 73 (1986) 321-337. |
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