[Energy state of the cerebral cortex of the cat during hyperventilation (author's transl)].
Average Po2 and Pco2, local blood flow and pH values in the cerebral cortex of the cat were measured during passive hyperventilation (arterial Pco2 below 19 mm Hg). At defined intervals tissue samples were taken for metabolite analysis. The object of the study was to correlate the data obtained on the brain surface with metabolic responses. Immediately after the start of hyperventilation blood flow decreased, average cortical tissue pressures of O2 and CO2 fell, and there was a simultaneous rise in cortical pH. At a later stage in the experiment the local blood supply reverted to its resting level. Despite a fivefold rise in tissue lactate level during hyperventilation and a decrease in local O2 pressure on the brain surface to 5-10 mm Hg the degree of phosphorylation of energy rich phosphates was not less than under normal conditions of oxygenation. Our investigations showed no evidence of energy lack in cerebral cortex cells during hyperventilation. Cellular hypoxia and its characteristics are defined. The possible causes of raised tissue lactate levels during hyperventilation despite the lack of evidence of cellular hypoxia are discussed.
D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D002415:Cats; D002540:Cerebral Cortex / Q000098:blood supply / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D004734:Energy Metabolism; D006863:Hydrogen-Ion Concentration; D006985:Hyperventilation / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D011773:Pyruvates / Q000378:metabolism
D007773:Lactates; D008293:Malates; D011773:Pyruvates; D002245:Carbon Dioxide; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D010100:Oxygen
Energiestatus der Grosshirnrinde der Katze bei Hyperventilation