Increase of cardiac work is associated with decrease of mitochondrial NADH
| Autor: | Hajo A. Bruining, J. F. Ashruf, J. M. C. C. Coremans, Can Ince |
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| Rok vydání: | 1995 |
| Předmět: |
Male
medicine.medical_specialty Physiology Cellular respiration Ultraviolet Rays Stimulation Biology Mitochondrion Fluorescence Oxygen Consumption Heart Rate Physiology (medical) Internal medicine Heart rate Respiration Pyruvic Acid medicine Animals Rats Wistar Pyruvates Cardiac Pacing Artificial Hemodynamics Heart NAD Mitochondria Rats Endocrinology Biochemistry Ventricular pressure NAD+ kinase medicine.symptom Cardiology and Cardiovascular Medicine Oxidation-Reduction Muscle contraction |
| Zdroj: | The American journal of physiology. 269(3 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | In this study we investigated the effect of work and substrate supply on mitochondrial NADH/NAD+ using epicardial autofluorescence in rat hearts perfused according to Langendorff. To avoid vasoconstrictor effects during high work output, nitroprusside-containing Tyrode solution was used. Photobleaching was avoided by using discontinuous ultraviolet excitation for NADH fluorescence measurements. To increase work, heartbeat rate was raised from 5 to 7 Hz, and concomitantly left ventricular pressure was raised stepwise from 0 to +/- 90 mmHg. During substrate-limited (5.5 mM glucose) perfusions, increase in O2 consumption (3.5 +/- 0.4 mumol.min-1.g-1, mean +/- SE, n = 6) caused by increase of heartbeat rate was associated with a significant decrease of NADH fluorescence (-31 +/- 2.5%, mean +/- SE, n = 6). During perfusions with 10 mM pyruvate increase of O2 consumption (3.6 +/- 0.7 mumol.min-1.g-1, mean +/- SE, n = 6) was associated with significant decrease of NADH fluorescence (-20 +/- 2.6%, mean +/- SE, n = 6). These results suggest that a rise in mitochondrial NADH/NAD+ is not the primary stimulus for increase in respiration and that changes of mitochondrial NADH/NAD+ are secondary to changes in O2 consumption. |
| Databáze: | OpenAIRE |
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