Effects of hydrostatic pressure (HP = 101 ATA) on nucleotides and pyridine dinucleotides tissue contents in trout.

Tissue concentrations of energetic nucleotides and coenzymes, and oxygen consumption (MO2), have been measured in trout, exposed for 30 min in normoxic conditions (PwO2 congruent to 150 Torr), to 101 ATA (Atmosphere Absolute) of hydrostatic pressure (HP) and compared with results obtained at atmospheric pressure (1 ATA). The results show that in trout exposed to HP, there is an increase in MO2 accompanied by a decrease in ATP and energy charge (EC) in the three tissues explored (brain, liver, and muscle). Moreover, the fall of EC in muscle is accompanied by an increase in inosine 5' monophosphate (IMP). These results are in agreement with the hypothesis of an histotoxic hypoxia induced by HP, which can act at the Krebs cycle level and/or at the respiratory chain level, possibly by uncoupling the respiratory chain from oxidative phosphorylation processes.