Regional cerebral glucose utilization rates in rats during asymptomatic period of exposure to 1, 2 and 3 atmospheres absolute of oxygen.
A previous study has shown an increase in regional cerebral metabolic rate for glucose prior to the onset of central nervous system oxygen toxicity in rats exposed to 5 atmospheres absolute of oxygen. The present study was designed to measure regional cerebral glucose utilization rates at pressures used for oxygen therapy and prolonged exposures during which rats are known to be asymptomatic. The regional metabolic rate for glucose in 26 brain structures and in gray and white matter of the thoracic and lumbar spinal cord was autoradiographically measured in awake unrestrained rats using the autoradiographic [14C]2-deoxyglucose technique. Femoral artery and vein cannulae were inserted 3 days before the experiment. Rats were divided into four groups of 15: (a) air control; (b) 6 h at 1 atmosphere absolute oxygen; (c) 4 h at 2 atmospheres oxygen; and (d) 2 h at 3 atmospheres oxygen. Statistically significant increases in glucose utilization (p less than 0.05) are seen only in lateral thalamus at 3 atmospheres oxygen, in superior olivary nucleus and inferior colliculus at 2 atmospheres oxygen and in superior olivary nucleus at 1 atmosphere oxygen. The combination of our previous data at 5 atmospheres oxygen and the present results at prolonged and safe exposures to lower pressures indicated that increased glucose utilization in some neuronal structures precedes the onset of the central nervous system manifestations of oxygen toxicity.
D000818:Animals; D001274:Atmospheric Pressure; D001921:Brain / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006931:Hyperbaric Oxygenation; D008297:Male; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism
D005947:Glucose