Regensburg 2004 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 50: Poster Session "Biological Physics"
AKB 50.105: Poster
Freitag, 12. März 2004, 10:30–13:00, B
Molecular dynamics of intramyocellular metabolites from high-resolution in vivo 1H NMR spectroscopy — •Leif Schröder1, Christian Schmitz2, and Peter Bachert1 — 1Dept. of Medical Physics in Radiology, Deutsches Krebsforschungszentrum, Heidelberg, Germany — 2Biophysikalische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Germany
Residual dipolar couplings affecting resonances in 1H NMR spectra of living tissue have been discovered 10 years ago (Kreis et. al.). Our purpose was to explore molecular dynamics of creatine (Cr), taurine (Tau), and carnosine (Cs) in human calf muscle (m. gastrocnemius) in vivo by analyzing dipolar-coupled multiplets in localized high-resolution 1H NMR spectra (STEAM and PRESS technique). Measurements were performed in healthy volunteers on a whole-body MR tomograph at B0 = 1.5 T. The residual coupling strength SD0 derived from the spectra was compared to the coupling constant D0 calculated using the internuclear distance under the assumption of completely frozen molecular libration. The order parameter S is a measure of molecular mobility. We found a large S (1.2 × 10−2) for the detectable Cs spin system, i.e. the imidazole ring protons, which indicates restricted reorientational motion of this compound in contrast to high mobilities of the CH2 and CH3 groups of Tau and Cr (S = 1.4 − 3 × 10−4). The observed motional restriction of Cs is explained by interaction of the metabolite with phospholipids in muscle cell membranes. These results demonstrate that 1H NMR spectroscopy permits noninvasive studies of intermolecular processes in vivo.