Investigational methodologies for the effects of brain maturation on energy transport.

Intracellular kinetics of high energy phosphate (HEP) is of fundamental importance in cellular biochemical physiology. In mammalian brain, intracellular HEP transport from the production site (mitochondria) to the consumption site (plasma membrane) is dependent on passive diffusion of HEP through the cytosol. Diffusivity of a substrate in a solution correlates inversely to the viscosity of the solution. The maturational process of mammalian brain involves dramatic changes in the cytosolic amino acid profile. Since the viscosity of a solution is a function of the diffusion coefficients of solutes and their concentrations, changes in the cytosolic amino acid composition should result in significant alteration in cytosol viscosity and hence, HEP diffusivity. Such a system is especially suitable for mathematical modeling and correlative analysis by in vivo nuclear magnetic resonance (NMR) spectroscopy. This brief review is written to provide a fundamental background for investigational methodologies on developmental neurobiology of cellular energetics.