<sup>1</sup>H NMR of intact muscle at 11 T

Arús, Carlos; Bárány, Michael; Westler, William M.; Markley, John L.

doi:10.1016/0014-5793(84)80175-1

Cited by 61 publications

(41 citation statements)

References 12 publications

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“…[23][24][25]), few have examined the quantification problem. Because of the need to suppress the intense Hz0 signal and to simplify the spectra, spinecho pulse sequences are used.…”

Section: Discussionmentioning

confidence: 99%

NMR‐invisible lactate in blood plasma

et al. 1988

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Resonances for lactate are broadened in 500 MHz 1H NMR spectra of human blood plasma and only about one‐third is visible in Hahn spin‐echo spectra. Similar effects are observed for some other carboxylate anions. Lactate added to the high‐M r fraction of plasma can give rise to peaks which are too broad to observe in either single‐pulse or spin‐echo spectra. Addition of agents such as NH4Cl of SDS dramatically increases the intensities of lactate peaks. Some glycoproteins appear to broaden lactate resonances.

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“…[23][24][25]), few have examined the quantification problem. Because of the need to suppress the intense Hz0 signal and to simplify the spectra, spinecho pulse sequences are used.…”

Section: Discussionmentioning

confidence: 99%

NMR‐invisible lactate in blood plasma

et al. 1988

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“…W e attribute the doublets to 14~-13c dipolar coupling, which is not averaged to zero because the '% quadrupolar interaction is comparable in magnitude to the "N Zeeman interaction (53)(54)(55)(56). The magnitude of the apparent splitting is proportional to the dipolar interaction, ~~~~h / 4~r~( r~~) 3 , the quadrupolar interaction, e2qQ/ h, its orientation with respect to rm, and the magnitude of the Zeeman interaction, B,. No attempt will be made to analyze these line shapes at this time; details for related compounds are presented in refs.…”

Section: Solid I3c Spectrum Of Carnosinementioning

confidence: 99%

“…Various suggestions have been made (2) as to its role in living organisms but its precise function is not well understood. Carnosine has been the subject of numerous 'H and I3C nmr investigations, even being detected with 'H nmr in intact muscle (3)(4)(5). However, there still seems to be ambiguity over some of the proton and carbon-13 assignments.…”

Section: Introductionmentioning

confidence: 99%

A ¹H and ¹³C nuclear magnetic resonance study of carnosine

Friedrich¹,

Wasylishen²

1986

Can. J. Chem.

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The proton and carbon-13 resonance signals of carnosine (β-alanyl-L-histidine) were unambiguously assigned using a variety of nmr techniques including proton–carbon chemical shift correlations, titrations of nmr chemical shifts, coupling constants, and isotope shifts. From the 13C nmr titration, carnosine's three pKa values were estimated to be 2.7, 7.1, and 10.6, and it was found that the imidazole ring existed predominantly as the 3-H tautomer in basic solution. Conformational information about the Cα—Cβ bond and about the N—Cα bond was deduced from observed 3J(C,H) and 3J(H,H) values. The 13C nmr spectrum of carnosine in solution is also compared with that obtained for a solid sample.

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“…Several authors have taken advantage of this pH sensitivity to measure the pH I of muscle in vivo and ex vivo (8 -13), and of muscle extracts (8,14). Specific applications have been made to muscle in resting (8,10,11,(13)(14)(15)(16), diseased (16), caffeinetreated (14), and exercised (9,11,12) states. Pan et al (11) and Hitzig et al (13) found high correlations between pH I measurements by the C-2 and P i methods.…”

mentioning

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The carnosine C‐2 proton's chemical shift reports intracellular pH in oxidative and glycolytic muscle fibers

Damon

Hsu

Stark

et al. 2003

Magnetic Resonance in Med

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The appearance of new peaks in the 7.7-8.6 and 6.8 -7.4 ppm regions of the postexercise 1 H spectrum of frog muscle is reported. These new peaks result from the splitting of single pre-exercise carnosine C-2 and C-4 peaks into two peaks, representing the intracellular pH (pH I ) of oxidative and glycolytic fibers. The following data support this conclusion: 1) comparison of means and regression analysis indicates equivalence of the pH I measurements by 1 H and 31 P NMR; 2) the pre-and poststimulation concentrations of carnosine are equal; 3) in ischemic rat hindlimb muscles, the presence of a single, more acidic peak in the plantaris; a single, less acidic peak in the soleus; and two peaks (more and less acidic) in the gastrocnemius correspond to published values for the fiber-type composition of these muscles; and 4) in muscles treated with iodoacetate prior to and during stimulation, a second peak never appears. These data indicate that it is feasible to measure separately the pH I of oxidative and glycolytic fibers using 1 H NMR spectroscopy. Measuring intracellular pH (pH I ) is important in studies of many cellular processes. In studies of muscle metabolism and exercise, it is desirable to measure separately the pH I of oxidative and glycolytic fibers. pH I measurements are commonly made using 31 P NMR spectroscopy, using the inorganic phosphate (P i ) peak's chemical shift. Following intense muscle exercise, the single pre-exercise P i peak frequently splits into two or more poststimulation P i peaks (P i,A and P i,B ), which are believed to correspond to P i in glycolytic and oxidative fibers, respectively (1-7). However, because of the low NMR sensitivity of the phosphorus nucleus, it is sometimes not possible to distinguish a P i peak from noise when the concentration of P i is low. Extreme broadening of the P i peak during exercise has also been observed (5), interfering with the ability to resolve individual peaks.The C-2 and C-4 protons on the imidazole ring of carnosine (␤-alanyl histidine) have pK A 's of approximately 7.0 and chemical shifts that are sensitive to pH in the physiological range, providing an alternative means of measuring pH noninvasively (8). Several authors have taken advantage of this pH sensitivity to measure the pH I of muscle in vivo and ex vivo (8 -13), and of muscle extracts (8,14). Specific applications have been made to muscle in resting (8,10,11,(13)(14)(15)(16), diseased (16), caffeinetreated (14), and exercised (9,11,12) states. Pan et al. (11) and Hitzig et al. (13) found high correlations between pH I measurements by the C-2 and P i methods.While studying exercising ex vivo frog gastrocnemii, we also observed the C-2 peak of carnosine at ϳ8.0 ppm prior to stimulation. However, we noted two peaks (one at ϳ8.53 and one at ϳ8.37 ppm) following exercise. In this study, we tested the hypothesis that they both originate from C-2 protons of carnosine. We also tested the hypothesis that the downfield peak (which we call carnosine C-2 A ) originates from a more acidic compartm...

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¹H NMR of intact muscle at 11 T

Cited by 61 publications

References 12 publications

NMR‐invisible lactate in blood plasma

NMR‐invisible lactate in blood plasma

A ¹H and ¹³C nuclear magnetic resonance study of carnosine

The carnosine C‐2 proton's chemical shift reports intracellular pH in oxidative and glycolytic muscle fibers

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1H NMR of intact muscle at 11 T

Cited by 61 publications

References 12 publications

NMR‐invisible lactate in blood plasma

NMR‐invisible lactate in blood plasma

A 1H and 13C nuclear magnetic resonance study of carnosine

The carnosine C‐2 proton's chemical shift reports intracellular pH in oxidative and glycolytic muscle fibers

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¹H NMR of intact muscle at 11 T

A ¹H and ¹³C nuclear magnetic resonance study of carnosine