A simple mathematical model of electron flow along the mitochondrial respir
atory cytochrome assembly and the transfer of electrons to molecular oxygen
is presented. First, an expression for the current-voltage relationship fo
r a biological oxygen electrode is derived, and from this the relationship
between oxygen consumption rate and oxygen partial pressure is determined.
An independent relationship between mitochondrial oxygen partial pressure a
nd oxygen supply rate is then derived. By eliminating oxygen partial pressu
re from these two expressions, we may obtain a relationship between oxygen
supply rate and oxygen consumption rate. This model is then used to investi
gate the effects of tissue dysoxia, uncoupling of oxidative phosphorylation
, increased cellular diffusional resistance and inhomogeneities in oxygen s
upply on oxygen consumption. It is concluded that each of the above contrib
ute in varying degrees to the phenomenon of "pathological oxygen supply dep
endency". (C) 2001 Academic Press.