ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
—The influence of hypothermia upon the metabolism of the brain was studied by reducing body temperature in N2O-anaesthetized rats to 32, 27 or 22°C, with subsequent measurements of organic phosphates, glycolytic metabolites, citric acid cycle intermediates and associated amino acids. Hypothermia was maintained for either 1 or 2 h and the effect of anaesthesia was evaluated by maintaining unanaesthetized animals at 22°C. Hypothermia had no influence on the cerebral cortical concentrations of ATP, ADP or AMP and there was only a small increase in phosphocreatine. Since the tissue concentrations of glucose and glycogen were reduced, it is concluded that the well known resistance of the hypothermie brain to ischaemia is unrelated to increased energy stores.Hypothermia was accompanied by decreases in the tissue concentrations of fructose-1,6-diphosphate, dihydroxyacetone phosphate, 3-phosphoglycerate, pyruvate, lactate, α-ketoglutarate, succinate and malate, but not of glucose-6-phosphate or citrate. These results indicate that metabolic flux is retarded mainly at the phosphofructokinase and isocitrate dehydrogenase steps. The largest relative reduction was seen in α-ketoglutarate, which was possibly secondary to accumulation of ammonia. There was no change in GABA, but a decrease in glutamate and increases in aspartate and alanine. These, changes are compatible with shifts in the aspartate and alanine aminotransferase reactions, possibly induced by the fall in α-ketoglutarate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1975.tb03858.x
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