scholarly journals Studies of acidosis in the ischaemic heart by phosphorus nuclear magnetic resonance

1979 ◽  
Vol 184 (3) ◽  
pp. 547-554 ◽  
Author(s):  
P B Garlick ◽  
G K Radda ◽  
P J Seeley
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Intracellular Ph ◽  
Superconducting Magnet ◽  
Perfused Heart ◽  
Global Ischaemia ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Significant Protective Effect ◽  
Nuclear Magnetic

1. Phosphorus-nuclear-magnetic-resonance measurements were made on perfused rat hearts at 37 degrees C. 2. With the improved sensitivity obtained by using a wide-bore 4.3 T superconducting magnet, spectra could be recorded in 1 min. 3. The concentrations of ATP, phosphocreatine and Pi and, from the position of the Pi resonance, the intracellular pH (pHi) were measured under a variety of conditions. 4. In a normal perfused heart pHi = 7.05 +/- 0.02 (mean +/- S.E.M. for seven hearts). 5. During global ischaemia pHi drops to 6.2 +/- 0.06 (mean +/- S.E.M.) in 13 min in a pseudoexponential decay with a rate constant of 0.25 min-1. 6. The relation between glycogen content and acidosis in ischaemia is studied in glycogen-depleted hearts. 7. Perfusion of hearts with a buffer containing 100 mM-Hepes before ischaemia gives a significant protective effect on the ischaemic myocardium. Intracellular pH and ATP and phosphocreatine concentrations decline more slowly under these conditions and metabolic recovery is observed on reperfusion after 30min of ischaemia at 37 degrees C. 8. The relation between acidosis and the export of protons is discussed and the significance of glycogenolysis in ischaemic acid production is evaluated.

Determination of chloride potential in perfused rat hearts by nuclear magnetic resonance spectroscopy

1992 ◽  
Vol 263 (6) ◽  
pp. H1958-H1962 ◽  
Author(s):  
R. Ramasamy ◽  
P. Zhao ◽  
W. L. Gitomer ◽  
A. D. Sherry ◽  
C. R. Malloy
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Heart Tissue ◽  
Disulfonic Acid ◽  
Resonance Spectroscopy ◽  
Dependent Change ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
High Concentrations ◽  
Nuclear Magnetic

Isolated beating rat hearts were perfused with trifluoroacetamide (TFM) and trifluoroacetate (TFA) and monitored by 19F-nuclear magnetic resonance (NMR). The average membrane TFA potential in spontaneously beating rat hearts, calculated according to standard principles assuming that TFA is distributed in its anionic form, was found to be -36.2 +/- 3.2 mV (n = 9) under normoxic conditions. In separate experiments, the chloride and potassium potentials were determined to be -38.5 +/- 3.6 mV (n = 7) and -85.3 +/- 3.3 mV (n = 7), respectively, from freeze-clamped heart tissue. In the presence of the anion-exchange inhibitor, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), TFA uptake into heart was significantly reduced, suggesting that TFA uptake occurs partly via the Cl(-)-HCO3- exchanger. Based on these results and the results of R. E. London and S. A. Gabel (Biochemistry 28: 2378–2382, 1989), we conclude that the distribution of TFA in hearts reflects the chloride potential (ECl) and not the membrane potential. A time-dependent change in the ECl occurs during global ischemia, and changes in ECl were also observed when the hearts were perfused with high concentrations of KCl. These results demonstrate that 19F-NMR may be utilized to monitor the ECl of perfused hearts under a variety of conditions.

scholarly journals A phosphorus-31 nuclear magnetic resonance investigation of intracellular environment in human normal and sickle cell blood

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 196-209 ◽  
Author(s):  
YF Lam ◽  
AK Lin ◽  
C Ho
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Intracellular Ph ◽  
Sickle Cell ◽  
Resonance Spectroscopy ◽  
Blood Samples ◽  
Intracellular Environment ◽  
Nuclear Magnetic

Abstract Intracellular pH and 2,3-diphosphoglycerate concentration in sickle cell amenia and normal human blood samples were measured by means of phosphorus-31 nuclear magnetic resonance spectroscopy. To monitor the concentrations of various internal phosphorylated metabolites of intact red blood cells, heparinized blood samples were used and were incubated at 37 degrees C with 5.6% C92, 25% O2, and 69.4% N2. The 31P chemical shifts of phosphorylated compounds, such as 2,3-diphosphoglycerate, adenosine 5′-triphosp-ate, and inorganic phosphate, depend on pH, and by using an appropriate calibration curve, the intracellular pH of intact erythrocytes can be obtained. The intracellular pH values in fresh sickl cell blood and normal blood were found to be 7.14 and 7.29, respectively. However, the whole-blood pH, as measured by a standard pH meter, was found to be 7.54 for both types of blood. The initial concentration of 2,3-diphosphoglycerate in sickle cell blood was about 30% higher, but it was depleted much faster during incubation than that in normal blood. The difference in intracellular pH between these two types of blood samples remained constant during incubation, even after depletion of 2,3-diphosphoglycerate. These results suggest that there are differences in intracellular environment between normal and sickle cell blood. Thus, 31P nuclear magnetic resonance spectroscopy provides a fast, direct, continuous, and noninvasive way to monitor the intracellular environment of intact erythrocytes.

An increase in intracellular [Na+] during Ca2+ depletion is not related to Ca2+ paradox damage in rat hearts

1998 ◽  
Vol 274 (3) ◽  
pp. H846-H852 ◽  
Author(s):  
Maurits A. Jansen ◽  
Cees J. A. Van Echteld ◽  
Tom J. C. Ruigrok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Creatine Kinase ◽  
Magnetic Resonance ◽  
Rate Pressure Product ◽  
Free Solution ◽  
Rat Hearts ◽  
Significant Change ◽  
Group Recovery ◽  
Isolated Rat ◽  
Nuclear Magnetic

Ca2+paradox damage has been suggested to be determined by Na+ entry during Ca2+ depletion and exchange of Na+ for Ca2+ during Ca2+ repletion. With the use of23Na nuclear magnetic resonance, we previously observed a Ca2+ paradox without a prior Na+ increase. We have now demonstrated a Na+ increase during Ca2+ and Mg2+ depletion without the occurrence of the Ca2+ paradox during Ca2+ repletion. Isolated rat hearts were perfused for 20 min with a Ca2+-free or a Ca2+- and Mg2+-free (Ca2+/Mg2+-free) solution under hypothermic conditions (20 and 25°C). Intracellular Na+ concentration ([Na+]i) increased from 11.9 ± 1.2 to 26.9 ± 5.8 mM ( P < 0.001) during Ca2+/Mg2+-free perfusion at 20°C, whereas no significant change in [Na+]ioccurred during 20 min of Ca2+-free perfusion at 20°C. In addition, we confirmed that [Na+]idid not change significantly during 20 min of normothermic Ca2+-free perfusion. Creatine kinase release during normothermic Ca2+ repletion in the 20°C groups was ∼10% and in the 25°C groups 75% of the release in the normothermia group. Recovery of rate-pressure product was ∼50% in the 20°C groups versus 0% in the normothermia group. In conclusion, hypothermic Ca2+/Mg2+-free perfusion results in a significant increase of [Na+]i, which does not contribute to the extent of the Ca2+ paradox on normothermic Ca2+ repletion.

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