Rate of cerebral ATP utilization in rats

Abstract
The rate of adenosinetriphosphate (ATP) disappearance in the brain after inhibition of aerobic and anaerobic metabolism was investigated. It was found that the rate increases with increasing age in the neonatal rat and that the effect of lowering the body temperature, which slows the rate, is greater in the 21-day rat than in the newborn. Calculation from the data gives 0.5 µm/sec/gm as the rate of high-energy phosphate utilization in the 21-day rat, and 0.04 µm/sec/gm in the 1-day rat. This increase in the rate of energy utilization during neonatal maturation is compared with the capacity to generate ATP; the utilization increase is found to be six times that of the capacity to generate ATP. The Q10 of the high-energy phosphate utilization in the 21-day rat is 1.7 in the 37°–25°C range, but is 10. in the 25°–15°C range. It is concluded that the rate of high-energy phosphate utilization is closely related to the amount of neuronal activity and, further, that the energy cost per average nerve impulse probably is greater in the adult brain than in the neonatal brain.