In response to
hypoxia at PO(2) 1.3-1.7 mg/L for 6 h, the kuruma prawn Marsupenaeus (Penaeus) japonicus showed a dramatic decrease in
phosphoarginine storage in muscle, with normal levels restored during 4-h post-hypoxic recovery. Large stores of muscle
glycogen only decreased between 4 and 6 h during
hypoxia, but greatly diminished during recovery. Muscle
ATP levels and energy charge decreased only slightly under
hypoxia.
Lactate levels increased slightly during
hypoxia and promptly returned to control levels during recovery. These data indicate that
phosphoarginine works in muscle as an
ATP buffer during
hypoxia and
glycogen is utilized as an energy source during recovery. Under
hypoxia, up- and down-regulated
proteins were identified after 2D electrophoresis and partial sequences were obtained after
protease digestion.
Fructose bisphosphate aldolase was down-regulated during
hypoxia, suggesting the suppression of glycolysis under
hypoxia. Several partial sequences from three
protein spots up-regulated under
hypoxia were all assigned to
arginine kinase, suggesting the existence of several
isoforms of
arginine kinase in the muscle of M. japonicus. This
arginine kinase up-regulation under
hypoxia may indicate a provision for
oxygen re-supply after anaerobiosis. This is consistent with the prompt replenishment of
phosphoarginine stores during recovery from
hypoxia.