Abstract
With a zero cerebral blood flow (CBF = 0) model of acute ischaemia in the gerbil brain, the development of ischaemic depolarisation (ID) was monitored by direct cortical current. This allowed us to evaluate an on-line, nonsampling scale of the degree of potential neuroprotection conferred by hypothermia in the 20-30°C range. Using the latent time (L) from onset of ischaemia to the resulting ID (the LID), it was found that at CBF = 0, the LID was inversely related to the brain temperature—at 30°C it was 2.7 times greater than at 37°C; 5.5 times at 25°C; and 7.7 times at 20°C. The protection afforded by hypothermia against ID followed a sigmoidal curve with the greatest increase between 25°C and 30°C. LID is a discrete, non-sampling method that can be used in combination with other modalities such as nuclear magnetic resonance to investigate the benefits of hypothermia for neuroprotection in ischaemic brain disease.
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