Endurance-Trained and Untrained Skeletal Muscle Bioenergetics Observed With Magnetic Resonance Spectroscopy

1996 ◽  
Vol 21 (4) ◽  
pp. 251-263 ◽  
Author(s):  
Bart M. Guthrie ◽  
Simon P. Frostick ◽  
David J. Mikulis ◽  
K. Wayne Marshall ◽  
Jack Goodman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Intracellular Ph ◽  
Adenosine Triphosphate ◽  
Inorganic Phosphate ◽  
Isometric Exercise ◽  
Oxidative Capacity ◽  
Resonance Spectroscopy ◽  
Trained Subjects

Resting and submaximal isometric exercise 31P magnetic resonance spectroscopy (MRS) was carried out on 7 endurance-trained males (26.0 ± 3 yrs) and 7 sedentary males (27.0 ± 4 yrs). Spectral analysis provided peak areas of phosphocreatine (PCr), inorganic phosphate (Pi), adenosine triphosphate (ATP), and the chemical shift of Pi relative to PCr. The ratio of PCr/Pi was moderately lower during rest (preexercise p =.13, postexercise p =.18), and significantly higher during exercise (p < .05) in the trained subjects. Intracellular pH patterns were the same for both groups; a transient alkalosis was observed at the onset of exercise with a return to resting levels after 2 min. Differences suggest improved ATP resynthesis rate in the trained subjects during exercise. Intracellular pH changes can be attributed to the utilization of hydrogen ions that accompany PCr hydrolysis during work. The findings are congruent with previous reports indicating a superior oxidative capacity in trained skeletal muscle. Key words: 31P MRS, isometric exercise, phosphocreatine, inorganic phosphate, adenosine triphosphate, intracellular pH

Fructose-1,6-Bisphosphate Preserves Adenosine Triphosphate but Not Intracellular pH during Hypoxia in Respiring Neonatal Rat Brain Slices 

1998 ◽  
Vol 88 (2) ◽  
pp. 461-472 ◽  
Author(s):  
Maryceline T. Espanol ◽  
Lawrence Litt ◽  
Koh Hasegawa ◽  
Lee-Hong Chang ◽  
Jeffrey M. Macdonald ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Intracellular Ph ◽  
Adenosine Triphosphate ◽  
Pentose Phosphate ◽  
Resonance Spectroscopy ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

Background Fructose-1,6-bisphosphate (FBP) sometimes provides substantial cerebral protection during hypoxia or ischemia. 31P/1H nuclear magnetic resonance spectroscopy of cerebrocortical slices was used to study the effects of FBP on hypoxia-induced metabolic changes. In addition, 13C-labeled glucose was administered and 13C nuclear magnetic resonance spectroscopy was used to search for FBP-induced modulations in glycolysis and the pentose-phosphate pathway. Methods In each experiment, 80 slices (350 microm) obtained from ten 7-day-old Sprague-Dawley rat litter mates were placed together in a 20-mm nuclear magnetic resonance tube, perfused, and subjected to 30 min of hypoxia (PO2 &lt; 3 mmHg). Nine experiments were performed, with n = 3 in each of three groups: (1) no treatment with FBP; (2) 60 min of prehypoxia treatment with FBP (2 mM); and (3) 60 min of posthypoxia treatment with FBP (2 mM). 31P/1H Interleaved nuclear magnetic resonance spectra at 4.7 T provided average adenosine triphosphate, intracellular pH, and lactate. Cresyl violet stains of random slices taken at predetermined time points were studied histologically. Some experiments had [2-13C]glucose in the perfusate. Slices from these studies were frozen for perchloric acid extraction of intracellular metabolites and studied with high-resolution 13C nuclear magnetic resonance spectroscopy at 11.75 T. Results With no pretreatment with FBP, hypoxia caused an approximately 50% loss of adenosine triphosphate, an approximately 700% increase in lactate, and a decrease in intracellular pH to approximately 6.4. Pretreatment with FBP resulted in no detectable loss of adenosine triphosphate, no increase in lactate, and minimal morphologic changes but did not alter decreases in intracellular pH. 13C Nuclear magnetic resonance spectra of extracted metabolites showed that pretreatment caused accumulation of [1-13C]fructose-6-phosphate, an early pentose-phosphate pathway metabolite. Posthypoxic treatment with FBP had no effects compared with no treatment. Conclusions During severe hypoxia, pretreatment with FBP completely preserves adenosine triphosphate and almost completely preserves cell morphology but does not alter hypoxia-induced decreases in intracellular pH. Pretreatment also substantially augments the flux of glucose into the pentose-phosphate pathway.

scholarly journals Evidence for a “metabolically inactive” inorganic phosphate pool in adenosine triphosphate synthase reaction using localized 31P saturation transfer magnetic resonance spectroscopy in the rat brain at 11.7 T

2016 ◽  
Vol 36 (9) ◽  
pp. 1513-1518 ◽  
Author(s):  
Brice Tiret ◽  
Emmanuel Brouillet ◽  
Julien Valette
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Rat Brain ◽  
Adenosine Triphosphate ◽  
Inorganic Phosphate ◽  
Reaction Rate ◽  
De Novo ◽  
Resonance Spectroscopy ◽  
Saturation Transfer ◽  
High Fields

With the increased spectral resolution made possible at high fields, a second, smaller inorganic phosphate resonance can be resolved on 31P magnetic resonance spectra in the rat brain. Saturation transfer was used to estimate de novo adenosine triphosphate synthesis reaction rate. While the main inorganic phosphate pool is used by adenosine triphosphate synthase, the second pool is inactive for this reaction. Accounting for this new pool may not only help us understand 31P magnetic resonance spectroscopy metabolic profiles better but also better quantify adenosine triphosphate synthesis.

Intracellular pH in lizards after hypercapnia

1995 ◽  
Vol 268 (4) ◽  
pp. R889-R895
Author(s):  
G. K. Snyder ◽  
J. R. Nestler ◽  
J. I. Shapiro ◽  
J. Huntley
Keyword(s):  
Skeletal Muscle ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Ion Transport ◽  
Intracellular Ph ◽  
Resonance Spectroscopy ◽  
Lizard Species ◽  
Dipsosaurus Dorsalis ◽  
Active Processes ◽  
Phi Regulation

We used the transmembrane distribution of 5,5-[2-14C]dimethyloxazolidine-2,4-dione ([14C]DMO) and 31P magnetic resonance spectroscopy (NMR) to investigate the effects of hypercapnia on intracellular pH (pHi) in brain and skeletal muscle of two lizard species: Anolis equestris and Dipsosaurus dorsalis. In control animals (normocapnic), plasma PCO2 (3.3 +/- 0.1 kPa) and plasma pH (7.52 +/- 0.01) for D. dorsalis were not significantly different from the values for A. equestris (2.8 +/- 0.2 kPa and 7.59 +/- 0.02, respectively). Furthermore 60 min of 5% CO2 increased plasma PCO2 and decreased plasma pH by the same amounts in both species. Brain pHi values determined with the DMO method were not significantly different from values determined with NMR. Control values of brain pHi (DMO, 7.16 +/- 0.01; NMR, 7.11 +/- 0.02) and muscle pHi were significantly higher for D. dorsalis (DMO, 7.15 +/- 0.03) than for A. equestris (DMO, 6.99 +/- 0.03; NMR, 7.02 +/- 0.02 for brain; DMO, 6.97 +/- 0.03 for muscle). In addition, changes in tissue pHi after 60 min of 5% CO2 were significantly different for the two species. In D. dorsalis muscle and brain pHi decreased significantly after hypercapnia, whereas in A. equestris muscle pHi decreased significantly but brain pHi was unchanged. Our findings were independent of the methods used to determine pHi. The smaller change in brain and muscle pHi than in plasma pH for A. equestris is consistent with the view that pHi regulation involves active processes such as transmembrane ion transport.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document