Application of the accurate assessment of intracellular magnesium and pH from the 31P shifts of ATP to cerebral hypoxia-ischemia in neonatal rat.
The authors present a high field in vivo demonstration of our 2-dimensional calibration methods for determining magnesium ion concentration ([Mg]), under conditions of fluctuating pH, from the three 31P NMR chemical shift differences of ATP. The effect of 3 h of hypoxic-ischemic insult (HI) on intracellular brain [Mg] was evaluated by using a well established 7-day-old rat model of cerebral HI. During the final hour of HI, there was a significant increase (P < 0.001) in free magnesium as well as in the ratio of total [Mg]/[ATP]. The normal, HI, and early (1-2 h) recovery values of free [Mg] were 0.336 +/- 0.015, 0.519 +/- 0.104, and 0.337 +/- 0.071 mM, respectively. These results are consistent with the temporal changes in [ATP]. Our assessment of [Mg] and pH for this high error measurement is general for most in vivo applications and may be routinely implemented.
Williams
G D
GD
Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey 17033, USA.
Smith
M B
MB
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001238:Asphyxia Neonatorum / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D002534:Hypoxia, Brain / Q000378:metabolism*; D007231:Infant, Newborn; D008274:Magnesium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D017208:Rats, Wistar
D000255:Adenosine Triphosphate; D008274:Magnesium