Maturational changes in intracellular high energy phosphate transport in rat brain

Maturational changes in intracellular high energy phosphate (HEP) transport in brain were investigated in rats in vivo using 31P nuclear magnetic resonance (NMR) diffusion spectroscopy and saturation transfer experiments. The diffusivities of phosphocreatine (PCr) and adenosine triphosphate (ATP) in adult brain were significantly higher than in newborn pup brain. The estimated diffusion lengths of PCr and ATP were similar in adult and newborn pup brain. The findings indicate firstly that the faster diffusivities of HEP effectively compensates for the higher energy demands in adult brain and secondly that ATP diffusion appears sufficient for brain HEP transport without need for a PCr shuttle mechanism.