Abstract
1H/31P NMR has followed the metabolic response to increased work in the glucose- and pyruvate-perfused rat myocardium during a heart cycle and at the steady state. With electrical pacing and dobutamine, the heart O2 consumption increases by 56%. The phosphocreatine (PCr) level initially declines, but recovers within 15 min to its control level; the oxymyoglobin (MbO2) saturation decreases by 15%. Because the MbO2 signal reflects the intracellular Po2, the capillary-to-cell O2 gradient has increased to match the increased O2 need. However, no transient metabolic fluctuation is observed in either PCr or MbO2 throughout the entire cardiac cycle in both glucose and pyruvate-/glucose-perfused hearts. No systolic-diastolic variation is detectable under either high workload or hypoxic conditions. The results reveal that neither O2 nor ADP is regulating respiration under increased energy demand in the steady or transient state.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 277 |
| Issue number | 4 46-4 |
| State | Published - Oct 1999 |
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Keywords
- Heart cycle
- Myoglobin
- Nuclear magnetic resonance
- Oxygen
- Phosphate metabolism
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
Regulation of respiration in myocardium in the transient and steady state. / Chung, Youngran; Jue, Thomas.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 277, No. 4 46-4, 10.1999.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Regulation of respiration in myocardium in the transient and steady state
AU - Chung, Youngran
AU - Jue, Thomas
PY - 1999/10
Y1 - 1999/10
N2 - 1H/31P NMR has followed the metabolic response to increased work in the glucose- and pyruvate-perfused rat myocardium during a heart cycle and at the steady state. With electrical pacing and dobutamine, the heart O2 consumption increases by 56%. The phosphocreatine (PCr) level initially declines, but recovers within 15 min to its control level; the oxymyoglobin (MbO2) saturation decreases by 15%. Because the MbO2 signal reflects the intracellular Po2, the capillary-to-cell O2 gradient has increased to match the increased O2 need. However, no transient metabolic fluctuation is observed in either PCr or MbO2 throughout the entire cardiac cycle in both glucose and pyruvate-/glucose-perfused hearts. No systolic-diastolic variation is detectable under either high workload or hypoxic conditions. The results reveal that neither O2 nor ADP is regulating respiration under increased energy demand in the steady or transient state.
AB - 1H/31P NMR has followed the metabolic response to increased work in the glucose- and pyruvate-perfused rat myocardium during a heart cycle and at the steady state. With electrical pacing and dobutamine, the heart O2 consumption increases by 56%. The phosphocreatine (PCr) level initially declines, but recovers within 15 min to its control level; the oxymyoglobin (MbO2) saturation decreases by 15%. Because the MbO2 signal reflects the intracellular Po2, the capillary-to-cell O2 gradient has increased to match the increased O2 need. However, no transient metabolic fluctuation is observed in either PCr or MbO2 throughout the entire cardiac cycle in both glucose and pyruvate-/glucose-perfused hearts. No systolic-diastolic variation is detectable under either high workload or hypoxic conditions. The results reveal that neither O2 nor ADP is regulating respiration under increased energy demand in the steady or transient state.
KW - Heart cycle
KW - Myoglobin
KW - Nuclear magnetic resonance
KW - Oxygen
KW - Phosphate metabolism
UR - http://www.scopus.com/inward/record.url?scp=0242533429&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0242533429&partnerID=8YFLogxK
M3 - Article
C2 - 10516176
AN - SCOPUS:0242533429
VL - 277
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 4 46-4
ER -