Simultaneous intracellular and extracellular pH measurement in the heart by 19F NMR of 6-fluoropyridoxol.
6-Fluoropyridoxol (6-FPOL) was evaluated as a simultaneous indicator of intracellular and extracellular pH and, hence, pH gradient in perfused rat hearts. After infusion, 19F NMR spectra rapidly showed two well-resolved peaks assigned to the intracellular and extracellular compartments, and pH was calculated on the basis of chemical shift with respect to a sodium trifluoroacetate standard. To demonstrate use of this molecule, dynamic changes in myocardial pH were assessed with a time resolution of 2 min during respiratory and metabolic alkalosis or acidosis and ischemia. For a typical heart, intracellular pH (pHi) = 7.14+/-0.01 and extracellular pH (pHe) = 7.52+/-0.02. In response to metabolic alkalosis, pHi remained relatively constant and the pH gradient increased. In contrast, respiratory challenge caused a significant increase in pHi. Independent measurements using pH electrodes and 31P NMR confirmed validity of the 19F NMR results.
Hunjan
S
S
Advanced Radiological Sciences, UT Southwestern Medical Center, Dallas, Texas 75235-9058, USA.
Mason
R P
RP
Mehta
V D
VD
Kulkarni
P V
PV
Aravind
S
S
Arora
V
V
Antich
P P
PP
D000472:Alkalosis, Respiratory / Q000378:metabolism; D000818:Animals; D005110:Extracellular Space / Q000378:metabolism*; D005462:Fluorine Radioisotopes; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D017202:Myocardial Ischemia / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D011730:Pyridoxal / Q000031:analogs & derivatives*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results
D005462:Fluorine Radioisotopes; D011730:Pyridoxal; C044385:6-fluoropyridoxal