| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Cortical spreading depression(CSD)is known to induce ischemic tolerance in a rat model of cerebral ischemia. CSD reduces volume of cerebral infarction in a focal ischemia model and attenuates hippocampal neuronal injury in a global ischemia model, when elicited 3 days prior to these insults. Recently, brain-derived neurotrophic factor(BDNF)has been shown to protect neurons against various insults in in vivo model. This study, therefore, investigated relationship between CSD-induced ischemic tolerance and expression of BDNF in rats. CSD was induced by applying KCl solution onto the cortex for 1 hour. For control animals, NaCl solution was used.Northern blot and in situ hybridization study showed that mRNA was dramatically upregulated biphasically in the ipsilateral cortex at 4 hours and 3 days in the CSD animals, but not in the controls. In the hippocampus, no detectable changes were not observed. For analysis of protein level, BDNF ELISA assay was performed. This study revealed that BDNF protein was also increased at 12 hours and 3 days post CSD in the ipsilateral cortex, but not in the hippocampus. The increase of BDNF mNA and protein coincided in time with the induction of ischemic tolerance in the cortex, but not in the hippocampus. These results suggested that increase of BDNF may be involved in the mechanism of endogenous mechanism of ischemic tolerance in the cortex.
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