31P NMR in vivo study of the acute effects of different doses of gamma-radiation on rat brain phosphate metabolism.
Changes in relative levels of brain phosphates and intracellular pH at selected time intervals after total gamma-irradiation of a rat at a single dose of 6.5 or 300 Gy were studied by 31P NMR in vivo. Irradiation yielded only minor changes in the spectra. Irradiation at a dose of 6.5 Gy caused a reversible decrease in Pi and an alkaline pH shift of 0.2 units after day 1, with no change in ATP. The signal, which consisted of alpha-ATP, alpha-ADP, NAD+/NADH and diphosphodiesters, declined after day 6, possibly due to a fall in NAD+/NADH concentration. Irradiation at a dose of 300 Gy led to an increase in ATP from 10 to 13% of total phosphates after day 1. Homeostasis of brain energy metabolism was characterized by the Z-index (normalized sample correlation coefficients averaged over the correlation matrix for NMR-measured phosphomonoesters, Pi, pH, phosphocreatine, gamma-ATP+beta-ADP, alpha-ATP+alpha-ADP+NAD+/NADH+diphosphodiesters and beta-ATP). The Z value rose from -0.18 +/- 0.02 to -0.02 +/- 0.02 by day 6 or from -0.19 +/- 0.02 to -0.07 +/- 0.02 by day 1 after irradiation at a dose of 6.5 or 300 Gy, respectively. This may indicate a pathological state of brain energetics as a system and a decrease in its stability.
Semenova
N A
NA
Institute of Chemical Physics, Russian Academy of Sciences, Moscow.
Yushmanov
V E
VE
Konradov
A A
AA
D000818:Animals; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004734:Energy Metabolism / Q000528:radiation effects*; D005720:Gamma Rays; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D010710:Phosphates / Q000378:metabolism*; D010759:Phosphorus Isotopes; D051381:Rats; D013997:Time Factors
D010710:Phosphates; D010759:Phosphorus Isotopes