[In vivo 1H and 31P NMR spectroscopy of the developing rat brain]

Postnatal development of mammalian brain is characterized by cell proliferation, migration, and differentiation of both neuronal and glial elements. These development process are accompanied by not only morphological changes but also biochemical changes. Nuclear magnetic resonance (NMR) spectroscopy is unique in its capability in obtaining metabolic information. In particular water-suppressed proton (1H) spectroscopy is a powerful tool that can be used to quantify certain intracellular amino acids and lactate. However, to date, no systematic analysis of the metabolic changes associated with brain development utilizing in vivo proton spectroscopy has appeared in the literature. In this study, we performed a non-invasive systematic investigation of the biochemical changes associated with brain maturation in the rat during the first 28 days postnatal in vivo utilizing both 1H and 31P spectroscopy. Phosphocreatine (PCr) was found to increase linearly during this period of development. Phosphomonoester (PME) was high at birth, peaked around the 10th day birth, and declined thereafter. N-acetyl-l-aspartate (NAA) was low at birth, increased in an approximately linear fashion, and reached adult levels by about day 28 postnatal. Choline was high at birth and showed a two step decline, at approximately day seven and day 20 postnatal. Taurine, a sulfur amino acid abundant in fetal brain, was also present in high levels on the first day postnatal.