Click on image to view larger version.

Fig. 4. Kinetics of frog skeletal muscle mitochondrial proton leak during normoxia
and in anoxia. During normoxia, the membrane potential is generated by the
electron-transport chain; however, during anoxia, the electron-transport chain
is inhibited, and the ATP synthase functions as an ATPase, pumping protons
from the matrix to the cytosol to preserve a certain membrane potential. The
normoxic and anoxic conditions are represented by filled and open circles,
respectively. Values are means ± S.E.M.; N=6 for both normoxia
and anoxia. *Resting proton leak rate and membrane potential.
Significant difference from the resting proton leak rate during normoxia
(P<0.05; Student's t-test).
Significant difference from the resting membrane potential
during normoxia (P<0.05; Student's t-test). From
St-Pierre et al. (2000b) with
permission.