Intracellular pH determination by 13C-NMR spectroscopy.
A noninvasive method for the determination of pH by the 13C-nuclear magnetic resonance (NMR) chemical shift of the C-3 carbon of sn-glycerol 3-phosphate is described. Nonlinear least-squares analysis of the chemical shift variation of the C-3 resonance of sn-glycerol 3-phosphate with pH at 37 degrees C in solutions and in perchloric acid extracts of tissue yielded a pKa of 6.2, making it a very sensitive indicator of pH in the approximate range of 5-7. Intracellular pH determined by the present 13C-NMR method correlated well with simultaneous measurements of pH by 31P-NMR spectroscopy over a wide range during normal perfusion and ischemic conditions in intact rat hearts. These findings indicate that this approach is particularly suited for quantification of intracellular pH over the physiological range in intact tissues and that observed in ischemic myocardium.
Chacko
V P
VP
Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
Weiss
R G
RG
D000818:Animals; D002247:Carbon Isotopes; D002250:Carbon Radioisotopes; D005994:Glycerophosphates; D006321:Heart / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D017202:Myocardial Ischemia / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000737:chemistry* / Q000648:ultrastructure*; D010758:Phosphorus; D051381:Rats; D017208:Rats, Wistar
D002247:Carbon Isotopes; D002250:Carbon Radioisotopes; D005994:Glycerophosphates; D010758:Phosphorus; C029620:alpha-glycerophosphoric acid