Lactate is an alternative energy fuel to glucose in neurons under anesthesia.

The uptake of [ 14 C]lactate was measured in the brains of mice anesthetized with pentobarbital or chloral hydrate. The results showed significant increase of the [ 14 C]lactate uptake in the brain under both anesthesia. Despite energy metabolism in the brain being suppressed by both pentobarbital and chloral hydrate, the [ 14 C]lactate uptake was unexpectedly increased under anesthesia. [ 14 C]Lactate uptake in rat brain injured by infusion of quinolic acid was significantly decreased, and the reduction of [ 14 C]lactate uptake was parallel to neural cell death, suggesting that exogenous lactate might be selectively taken up by neuron. These results indicated that lactate rather than glucose might serve as an energy substrate for neuron in intact brain under anesthesia.