Metabolic responses of the awake cerebral cortex to anoxia hypoxia spreading depression and epileptiform activity

Avraham Mayevsky, Britton Chance

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

Using the time sharing fluoremeter/reflectometer the measurement of NADH fluorescence as well as the reflected light was obtained from the surface of the awake rat brain cortex. The light was transferred to and from the brain via a flexible light pipe (made of quartz fibers) connected to a cannula implanted permanently above the brain. Exposing the rat to pure nitrogen atmosphere increased the fluorescence (reduction of NADH) by 32.3 ± 6.1 in comparison to the normoxic fluorescence level. During cortical spreading depression (SD) the NADH fluorescence decreased (oxidation of NADH) by 17.3 ± 2.8%. Exposing the rat to nitrogen after SD was elicited blocked the oxidation cycle observed during SD. Exposing the awake rats to 10, 7.5 or 5% O2 did not block the response of the brain to spreading depression or to Metrazol applied locally to the cortex. Under hypoxic conditions the brain showed a typical response to SD, namely, an oxidation cycle of NADH except that the duration of the cycle was longer and the decrease in the NADH level was smaller. The EEG activity recovered to normal even under 5%. The same effect of hypoxia was found when Metrazol was applied and epileptic activity was developed.

Original languageEnglish
Pages (from-to)149-165
Number of pages17
JournalBrain Research
Volume98
Issue number1
DOIs
StatePublished - 7 Nov 1975
Externally publishedYes

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