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Dynamics of tissue oxygenation in isolated rabbit heart as measured with near-infrared spectroscopy.
Am J Physiol. 1999 05; 276(5):H1616-24.AJ

Abstract

We investigated the role of myoglobin (Mb) in supplying O2 to mitochondria during transitions in cardiac workload. Isovolumic rabbit hearts (n = 7) were perfused retrogradely with hemoglobin-free Tyrode solution at 37 degrees C. Coronary venous O2 tension was measured polarographically, and tissue oxygenation was measured with two-wavelength near-infrared spectroscopy (NIRS), both at a time resolution of approximately 2 s. During transitions to anoxia, 68 +/- 2% (SE) of the NIRS signal was due to Mb and the rest to cytochrome oxidase. For heart rate steps from 120 to 190 or 220 beats/min, the NIRS signal decreased significantly by 6.9 +/- 1.3 or 11.1 +/- 2.1% of the full scale, respectively, with response times of 11.0 +/- 0.8 or 9.1 +/- 0.5 s, respectively. The response time of end-capillary O2 concentration ([O2]), estimated from the venous [O2], was 8.6 +/- 0.8 s for 190 beats/min (P < 0.05 vs. NIRS time) or 8.5 +/- 0.9 s for 220 beats/min (P > 0.05). The mean response times of mitochondrial O2 consumption (VO2) were 3.7 +/- 0.7 and 3.6 +/- 0.6 s, respectively. The deoxygenation of oxymyoglobin (MbO2) accounted for only 12-13% of the total decrease in tissue O2, with the rest being physically dissolved O2. During 11% reductions in perfusion flow at 220 beats/min, Mb was 1.5 +/- 0.4% deoxygenated (P < 0.05), despite the high venous PO2 of 377 +/- 17 mmHg, indicating metabolism-perfusion mismatch. We conclude that the contribution of MbO2 to the increase of VO2 during heart rate steps in saline-perfused hearts was small and slow compared with that of physically dissolved O2.

Authors+Show Affiliations

Laboratory for Physiology, Institute for Cardiovascular Research, Vrije Universiteit, 1081 BT Amsterdam, The Netherlands. b.de_groot.physiol@med.vu.nlNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

10330246

Citation

de Groot, B, et al. "Dynamics of Tissue Oxygenation in Isolated Rabbit Heart as Measured With Near-infrared Spectroscopy." The American Journal of Physiology, vol. 276, no. 5, 1999, pp. H1616-24.
de Groot B, Zuurbier CJ, van Beek JH. Dynamics of tissue oxygenation in isolated rabbit heart as measured with near-infrared spectroscopy. Am J Physiol. 1999;276(5):H1616-24.
de Groot, B., Zuurbier, C. J., & van Beek, J. H. (1999). Dynamics of tissue oxygenation in isolated rabbit heart as measured with near-infrared spectroscopy. The American Journal of Physiology, 276(5), H1616-24. https://doi.org/10.1152/ajpheart.1999.276.5.H1616
de Groot B, Zuurbier CJ, van Beek JH. Dynamics of Tissue Oxygenation in Isolated Rabbit Heart as Measured With Near-infrared Spectroscopy. Am J Physiol. 1999;276(5):H1616-24. PubMed PMID: 10330246.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dynamics of tissue oxygenation in isolated rabbit heart as measured with near-infrared spectroscopy. AU - de Groot,B, AU - Zuurbier,C J, AU - van Beek,J H, PY - 1999/5/18/pubmed PY - 1999/5/18/medline PY - 1999/5/18/entrez SP - H1616 EP - 24 JF - The American journal of physiology JO - Am. J. Physiol. VL - 276 IS - 5 N2 - We investigated the role of myoglobin (Mb) in supplying O2 to mitochondria during transitions in cardiac workload. Isovolumic rabbit hearts (n = 7) were perfused retrogradely with hemoglobin-free Tyrode solution at 37 degrees C. Coronary venous O2 tension was measured polarographically, and tissue oxygenation was measured with two-wavelength near-infrared spectroscopy (NIRS), both at a time resolution of approximately 2 s. During transitions to anoxia, 68 +/- 2% (SE) of the NIRS signal was due to Mb and the rest to cytochrome oxidase. For heart rate steps from 120 to 190 or 220 beats/min, the NIRS signal decreased significantly by 6.9 +/- 1.3 or 11.1 +/- 2.1% of the full scale, respectively, with response times of 11.0 +/- 0.8 or 9.1 +/- 0.5 s, respectively. The response time of end-capillary O2 concentration ([O2]), estimated from the venous [O2], was 8.6 +/- 0.8 s for 190 beats/min (P < 0.05 vs. NIRS time) or 8.5 +/- 0.9 s for 220 beats/min (P > 0.05). The mean response times of mitochondrial O2 consumption (VO2) were 3.7 +/- 0.7 and 3.6 +/- 0.6 s, respectively. The deoxygenation of oxymyoglobin (MbO2) accounted for only 12-13% of the total decrease in tissue O2, with the rest being physically dissolved O2. During 11% reductions in perfusion flow at 220 beats/min, Mb was 1.5 +/- 0.4% deoxygenated (P < 0.05), despite the high venous PO2 of 377 +/- 17 mmHg, indicating metabolism-perfusion mismatch. We conclude that the contribution of MbO2 to the increase of VO2 during heart rate steps in saline-perfused hearts was small and slow compared with that of physically dissolved O2. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/10330246/Dynamics_of_tissue_oxygenation_in_isolated_rabbit_heart_as_measured_with_near_infrared_spectroscopy_ L2 - http://journals.physiology.org/doi/full/10.1152/ajpheart.1999.276.5.H1616?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -