Fish muscle energy metabolism measured by in vivo 31P-NMR during anoxia and recovery.
By means of in vivo 31P nuclear magnetic resonance (NMR) we measured energy stores and intracellular pH at 10-min intervals in the myotome of unanesthetized carp and goldfish before, during, and after a period of anoxia (1 h for carp and 4 h for goldfish). The fish were mounted in a modified bioprobe, and their gills were irrigated with a constant flow of aerated or anoxic water. Anoxia caused a steep decline of phosphocreatine and intracellular pH in carp muscle. After the phosphocreatine stores had been exhausted by greater than 85%, [ATP] fell, whereas IMP and phosphodiesters accumulated. In goldfish muscle, initial changes followed the same pattern, but after 20 min a steady state of high-energy phosphates was reached and the development of acidosis was dampened. The resistance of goldfish to anoxia is due to metabolic suppression and a switch from lactate to ethanol and CO2 as the anaerobic end products. In both species, recovery was complete within 3 h. The fast pH recovery seems to be mainly caused by H+ and lactic acid efflux.
van den Thillart
G
G
Department of Biology (Animal Physiology), Gorlaeus Laboratories, University of Leiden, The Netherlands.
van Waarde
A
A
Muller
H J
HJ
Erkelens
C
C
Addink
A
A
Lugtenburg
J
J
D000255:Adenosine Triphosphate / Q000378:metabolism; D000693:Anaerobiosis; D000818:Animals; D003530:Cyprinidae / Q000378:metabolism*; D004734:Energy Metabolism; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism*; D007291:Inosine Monophosphate / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism
D010710:Phosphates; D010725:Phosphocreatine; D007291:Inosine Monophosphate; D000255:Adenosine Triphosphate