AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 6 1144-R1150, Copyright © 1986 by American Physiological Society
Function of myoglobin in oxygen consumption by isolated perfused fish hearts
J. R. Bailey and W. R. Driedzic
Myoglobin, an intracellular O2-binding protein, plays a protective role in
maintaining performance of isolated fish hearts under hypoxic conditions.
This study was designed to test the hypothesis that the protein contributes
to O2 consumption under conditions of increased O2 demand or hypoxia.
Isolated myoglobin-rich sea raven (Hemitripterus americanus) hearts and
myoglobin-poor ocean pout (Macrozoarces americanus) hearts were perfused
under conditions of changing partial pressure of O2 (PO2) and afterload.
Sea raven hearts maintained O2 consumption and cardiac performance at low
PO2 and high afterload, whereas ocean pout hearts did not. In other cases
sea raven and ocean pout hearts were treated with hydroxylamine, which
renders myoglobin incapable of binding O2, and subjected to changing PO2
and afterload. Sea raven hearts could not maintain O2 consumption and
cardiac performance, whereas hydroxylamine treatment had no effect on O2
consumption in ocean pout hearts under these conditions. These data provide
the first evidence to support the concept that myoglobin plays a role in O2
consumption of hearts.
