Effect of hypocapnia on local cerebral glucose utilization in rats.
The effect of hypocapnia on regional cerebral glucose utilization (L-CMRg) was studied in 14 Sprague Dawley rats. After cannulation of femoral vessels, halothane was discontinued and anesthesia was maintained with 70% N2O in oxygen. The animals' lungs were mechanically ventilated to achieve normocapnia (PaCO2 = 40 +/- 2 mmHg) in group A or hypocapnia (PaCO2 = 25 +/- 2 mmHg) in group B. L-CMRg was measured by the 14C-2-deoxyglucose autoradiographic method. Twenty-six anatomically discrete structures representing cortical, subcortical, limbic, and brainstem areas were studied. In hypocapnic animals, mean values for L-CMRg were higher in 25 out of 26 structures studied. The increase in L-CMRg was heterogenous. The structures that had higher L-CMRg during normocapnia showed the greatest increase in L-CMRg. When the two groups were compared using a profile analysis, in six regions (lateral and ventral thalamus, inferior colliculus, lateral habenulla, medial geniculate body, and auditory cortex), a value of P less than 0.05 was obtained.
Samra
S K
SK
Department of Anesthesiology, University of Texas Medical Branch, Galveston 77550-2778.
Turk
P
P
Arens
J F
JF
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001921:Brain / Q000378:metabolism*; D002245:Carbon Dioxide / Q000097:blood / Q000172:deficiency*; D002250:Carbon Radioisotopes; D003847:Deoxyglucose / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D006221:Halothane; D008297:Male; D009609:Nitrous Oxide; D010100:Oxygen; D051381:Rats; D011919:Rats, Inbred Strains; D012121:Respiration, Artificial
D001786:Blood Glucose; D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D003847:Deoxyglucose; D005947:Glucose; D009609:Nitrous Oxide; D010100:Oxygen; D006221:Halothane