pH-lactate dissociation in neonatal anoxia: Proton and ³¹P NMR spectroscopic studies in rat pups

The pH controlling capability of brain of 1-day-old rat pups was investigated using proton (¹H) and phosphorus-31 (³¹P) nuclear magnetic resonance (NMR) in vivo spectroscopy. Despite significantly high levels of lactate accumulation, brain of 1-day-old pups showed remarkable capability of maintaining brain pH virtually unchanged throughout 22 min of anoxia. The study supports the concepts that lactic acidosis is one of the important factors determining the outcome of cerebral anoxia and that the significantly higher pH controlling capability of immature brain plays a key role in the higher resistance toward anoxia.