Correlation Between Freeze-Trapped Brain and In Vivo Mitochondrial NADH Measurements

The interrelation between the metabolic responses to ischemia and seizure propensity was studied in two groups of seizure-prone (SP) and nonseizure-prone (NSP) gerbils. The metabolic state was evaluated in vivo using the light guide surface fluorometry as well as in the frozen brain scanned at liquid N2 temperature for the flavoproteins/pyridine nucleotides ratio after monitoring the brain in vivo. The results could be summarized as follows. (1) Unilateral carotid artery occlusion led to partial ischemia in the ipsilateral hemisphere while the contralateral hemisphere remained normoxic. (2) Animal variability in the degree of the ischemia insult due to unilateral occlusion was not side-dependent or in correlation with seizure propensity. (3) A significant correlation was found between the NADH increase during ischemia and the redox state measurements done in the same brain after funnel freezing with liquid nitrogen. (4) In a large number of the gerbils (not depending on the origin or strain), a peculiar interhemispheric blood supply connection was found. A narrow band (1 mm in width) of tissue near the midline obtained its blood via the same vessels supplying the contralateral hemisphere. (5) We did not find any correlation between blood vessel anatomy in the brain and seizure propensity.