Improvement in the efficiency of oxidative phosphorylation in the freshwater eel acclimated to 10.1 MPa hydrostatic pressure

Previous studies have suggested that the efficiency of oxidative phosphoryl ation in the freshwater eel (Anguilla anguilla) is increased after acclimat ion to high hydrostatic pressure. Analysis at atmospheric pressure of the r espiratory chain complexes showed that, after 21 days at 10.1 MPa, the acti vity of complex II was decreased to approximately 50% (P<0.01) of the contr ol value and that cytochrome c oxidase (complex IV) activity was significan tly increased to 149% of the control value (P<0.05). ADP/O ratios calculate d from mitochondrial respiration measurements were significantly increased after acclimation to high hydrostatic pressure (2.87 versus 2.52, P<0.001) when measured in the presence of pyruvate plus malate at atmospheric pressu re. These results clearly show an increased oxidative phosphorylation effic iency in response to high-pressure acclimation.