Regulation of murine myocardial energy metabolism during adrenergic stress studied by in vivo 31P NMR spectroscopy

A. V. Naumova, R. G. Weiss, V. P. Chacko

Research output: Contribution to journalArticlepeer-review

Abstract

Image-guided, spatially localized 31P magnetic resonance spectroscopy (MRS) was used to study in vivo murine cardiac metabolism under resting and dobutamine-induced stress conditions. Intravenous dobutamine infusion (24 μg · min-1 · kg body wt-1) increased the mean heart rate by ∼39% from 482 ± 46 per min at baseline to 669 ± 77 per min in adult mice. The myocardial phosphocreatine (PCr)-to-ATP (PCr/ATP) ratio remained unchanged at 2.1 ± 0.5 during dobutamine stress, compared with baseline conditions. Therefore, we conclude that a significant increase in heart rate does not result in a decline in the in vivo murine cardiac PCr/ATP ratio. These observations in very small mammals, viz., mice, at extremely high heart rates are consistent with studies in large animals demonstrating that global levels of high-energy phosphate metabolites do not regulate in vivo myocardial metabolism during physiologically relevant increases in cardiac work.

Original languageEnglish (US)
Pages (from-to)H1976-H1979
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume285
Issue number5 54-5
DOIs
StatePublished - Nov 2003

Keywords

  • Cardiac metabolism
  • Dobutamine stress
  • Magnetic resonance spectroscopy
  • PCr-to-ATP ratio

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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