Effects of age on apparent ³¹P spin–lattice relaxation times of rat brain phosphates

Abstract

Apparent 31P spin-lattice relaxation times have been measured in vivo for brain phosphates in young adult, mature adult, and aged rats at 4.7 T and 35 degrees C. Statistically significant differences were found for most phosphate species, except PCr and gamma-ATP, among the three age groups, particularly between the young and mature adults. Age-related changes in tissue composition and exchange reactions are discussed as possible contributors to these results.

Nuclear Magnetic Resonance Spectroscopy Study on Energy Metabolism, Intracellular pH, and Free Mg2+ Concentration in the Brain of Transgenic Mice Overexpressing Human Ornithine Decarboxylase Gene

“…"P spectra were acquired with pulses of 20 ps in duration, a spectral width of 10 kHz, and 2,048 data points. The interpulse interval was either 1.2 or 2.7 s. Both pulsing conditions allow for full relaxation of ATP resonances in the brain (Stolk et al, 1987) but not that of phosphocreatine (PCr), and therefore peak area ratios do not correspond directly to concentration ratios. The data have not been corrected for the saturation, as the acquisition conditions for the "P spectra that were used for analysis of PCr/P-ATP ratios were the Same (interpulse interval, 2.7 s).…”