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Myocardial oxygenation in the isolated working rabbit heart as a function of work.
Am J Physiol. 1992 Jan; 262(1 Pt 2):H255-67.AJ

Abstract

Myocardial O2 consumption (MVO2) was stimulated up to two-fold by either increasing afterload or beta-receptor stimulation in working normothermic isolated rabbit hearts while noninvasively monitoring the O2 delivery or phosphate compounds (total n = 48). Intracellular O2 delivery was estimated with the use of myocardial optical absorbance changes centered at 603.5 and 582 nm that correlate with cytochrome aa3 redox and myoglobin oxygenation states. Phosphate-containing metabolites (ATP, phosphocreatine, free ADP) were assessed using 31P nuclear magnetic resonance spectroscopy. Measurements were made both with intact autoregulation and after maximal vasodilation by 1 microM nitroprusside (NP). When afterload was used to increase MVO2, absorbance decreased at 603.5 nm and increased at 582 nm, consistent with a 10-15% increase in myocardial oxygenation, without an associated change in cardiac phosphate compounds. NP caused a further increase in myocardial oxygenation and venous PO2 consistent with an increase in the O2 supply-to-demand ratio. Increases in MVO2 due to beta-stimulation alone were not associated with changes in 603.5-nm absorbance or phosphate compounds, but in combination with NP were accompanied by increased oxygenation, venous PO2, and cardiac phosphocreatine. KCl arrest caused maximal increases in oxygenation and phosphocreatine. These findings suggest that neither cytochrome aa3 nor myoglobin in the isolated working rabbit heart is fully oxidized or oxygenated, respectively. Furthermore, the oxygenation state of the tissue varied both with afterload-induced changes in cardiac work and with changes in O2 supply/demand.

Authors+Show Affiliations

Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1346358

Citation

Heineman, F W., et al. "Myocardial Oxygenation in the Isolated Working Rabbit Heart as a Function of Work." The American Journal of Physiology, vol. 262, no. 1 Pt 2, 1992, pp. H255-67.
Heineman FW, Kupriyanov VV, Marshall R, et al. Myocardial oxygenation in the isolated working rabbit heart as a function of work. Am J Physiol. 1992;262(1 Pt 2):H255-67.
Heineman, F. W., Kupriyanov, V. V., Marshall, R., Fralix, T. A., & Balaban, R. S. (1992). Myocardial oxygenation in the isolated working rabbit heart as a function of work. The American Journal of Physiology, 262(1 Pt 2), H255-67.
Heineman FW, et al. Myocardial Oxygenation in the Isolated Working Rabbit Heart as a Function of Work. Am J Physiol. 1992;262(1 Pt 2):H255-67. PubMed PMID: 1346358.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Myocardial oxygenation in the isolated working rabbit heart as a function of work. AU - Heineman,F W, AU - Kupriyanov,V V, AU - Marshall,R, AU - Fralix,T A, AU - Balaban,R S, PY - 1992/1/1/pubmed PY - 1992/1/1/medline PY - 1992/1/1/entrez SP - H255 EP - 67 JF - The American journal of physiology JO - Am. J. Physiol. VL - 262 IS - 1 Pt 2 N2 - Myocardial O2 consumption (MVO2) was stimulated up to two-fold by either increasing afterload or beta-receptor stimulation in working normothermic isolated rabbit hearts while noninvasively monitoring the O2 delivery or phosphate compounds (total n = 48). Intracellular O2 delivery was estimated with the use of myocardial optical absorbance changes centered at 603.5 and 582 nm that correlate with cytochrome aa3 redox and myoglobin oxygenation states. Phosphate-containing metabolites (ATP, phosphocreatine, free ADP) were assessed using 31P nuclear magnetic resonance spectroscopy. Measurements were made both with intact autoregulation and after maximal vasodilation by 1 microM nitroprusside (NP). When afterload was used to increase MVO2, absorbance decreased at 603.5 nm and increased at 582 nm, consistent with a 10-15% increase in myocardial oxygenation, without an associated change in cardiac phosphate compounds. NP caused a further increase in myocardial oxygenation and venous PO2 consistent with an increase in the O2 supply-to-demand ratio. Increases in MVO2 due to beta-stimulation alone were not associated with changes in 603.5-nm absorbance or phosphate compounds, but in combination with NP were accompanied by increased oxygenation, venous PO2, and cardiac phosphocreatine. KCl arrest caused maximal increases in oxygenation and phosphocreatine. These findings suggest that neither cytochrome aa3 nor myoglobin in the isolated working rabbit heart is fully oxidized or oxygenated, respectively. Furthermore, the oxygenation state of the tissue varied both with afterload-induced changes in cardiac work and with changes in O2 supply/demand. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/1346358/Myocardial_oxygenation_in_the_isolated_working_rabbit_heart_as_a_function_of_work_ L2 - http://journals.physiology.org/doi/full/10.1152/ajpheart.1992.262.1.H255?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -