Carbon monoxide inhibition of regulatory pathways in myocardium

Alan Glabe, Youngran Chung, X. U. Dejun, Thomas Jue

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

The 1H nuclear magnetic resonance (NMR) myoglobin (Mb) Val E11 signal provides a unique opportunity to assess the functional role of Mb in the cell. On CO infusion in perfused myocardium, the MbO2 signal at -2.76 parts per million (ppm) gradually disappears, whereas the corresponding MbCO signal emerges at -2.26 ppm, reflecting the state of Mb inhibition. Up to 76.8% MbCO saturation, myocardial O2 consumption (MV̇O2) remains constant, whereas the rate-pressure product (RPP) has already dropped to 92% of the control level. At 87.6% MbCO saturation, the lactate formation rate has increased by a factor of two, and ṀO2 begins to decline. However, the ratio CO/O2 is still 1/10, well below the inhibition threshold for cytochrome oxidase activity. The ṀO2 decline in the face of an adequate O2 supply and an unperturbed high-energy phosphate level implies that Mb may play a role in directly regulating respiration, mediated potentially by a shift in NADH/NAD. Although nitrite inhibits Mb, nitrite also directly affects the myocardial function.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume274
Issue number6 43-6
StatePublished - 1998

Keywords

  • Myoglobin
  • Nuclear magnetic resonance
  • Oxidative phosphorylation
  • Respiration

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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