Brain energy metabolism in two kinds of total asphyxia: an in vivo phosphorus nuclear magnetic resonance spectroscopic study.

Brain energy metabolism was studied in vivo by means of 31P-NMR spectroscopy in newborn mice during and after 20-minutes exposure to either pure carbon dioxide gas or nitrogen gas. In the N2 group, the brain ATP concentration remained almost normal throughout the experiment, while it showed a 30% reduction in the CO2 group. The brain concentration of phosphocreatine dropped to about 20% of the control value during the asphyxia in both groups, and its recovery was significantly delayed in the CO2 group compared to in the N2 group. Tissue acidosis and Pi accumulation were more remarkable and prolonged in the CO2 group.