Cerebral oxidized and reduced nicotinamide-adenine dinucleotide phosphate and glucose 6-phosphate dehydrogenase in mice during exposure to high oxygen pressure.
NADP+, NADPH and glucose 6-phosphate dehydrogenase were determined in the cerebral cortex of mice exposed to high O2 pressure for 0, 8 and 16 min. These time intervals corresponded to 0, 50 and 100% of the CT50 (the time taken for 50% of the mice to convulse). Cerebral NADP+, NADPH and glucose 6-phosphate dehydrogenase also were determined in O2-exposed mice exhibiting hyperactivity, convulsions, and in mice killed 10s after convulsions. Similar increases in cortical NADP+ and decreases in NADPH were found in mice exposed to 610kPa (6 atm.) of 100% O2 for 0, 50 and 100% of the CT50, during hyperactivity, onset of seizure and 10s after convulsions. The NADP+/NADPH ratio increased approx. 25% at 0% of the CT50, and remained at this increased value at all O2-exposure periods including the hyperactive state, onset of seizure and 10s after convulsions. Identical changes in cerebral NADP+ , NADPH and the NADP+/NADPH ratio were found in mice exposed for 16min to 100% O2 at 100, 350 or 610kPa. No change in cerebral glucose 6-phosphate dehydrogenase was found in mice exposed to 610kPa of 100% O2 during the various stages of O2 toxicity. Only in the 10s post-convulsive group was a statistically significant decrease in glucose 6-phosphate dehydrogenase observed. Disulfiram [bis(diethylthiocarbamoyl) disulphide], an effective O2-protective agent, did not prevent the O2-induced increase in cerebral NADP+ and the NADP+/NADPH ratio, or decrease in NADPH.
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004221:Disulfiram / Q000494:pharmacology; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D006931:Hyperbaric Oxygenation; D008297:Male; D051379:Mice; D009249:NADP / Q000378:metabolism*; D010100:Oxygen / Q000633:toxicity*; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism
D009249:NADP; D005954:Glucosephosphate Dehydrogenase; D010100:Oxygen; D004221:Disulfiram