TY - JOUR
T1 - Effect of brain, body, and magnet bore temperatures on energy metabolism during global cerebral ischemia and reperfusion monitored by magnetic resonance spectroscopy in rats
AU - Shimizu, Hiroaki
AU - Chang, Lee Hong
AU - Litt, Lawrence
AU - Zarow, Gregory
AU - Weinstein, Philip R.
PY - 1997/6/1
Y1 - 1997/6/1
N2 - To record brain temperature for comparison with rectal and temporalis muscle temperatures in preliminary studies before MR spectroscopy experiments, a thermistor was inserted into the basal ganglia in eight anesthetized, ventilated, and physiologically monitored rats. The rats were placed in an MR spectrometer and subjected to 60 min of global cerebral ischemia and 2 h of reperfusion without radiofrequency (RF) pulsing. Body temperature was maintained at 37.5-38.0°C (normothermia) or 36.5-37.0°C (mild hypothermia). Brain temperature during ischemia, which dropped to 31.9 ± 0.3 (hypothermia) and 33.6 ± 0.5°C (normothermia), correlated with temporalis muscle temperature (r2 = 0.92) but not with body or magnet bore temperature measurements. Ischemia reduced brain temperature approximately 1.7°C in rats subjected to mild hypothermia (1°reduction of body temperature). Parallel MR spectroscopy experiments showed no significant difference in energy metabolites between normothermic and hypothermic rats during ischemia. However, the metabolic recovery was more extensive 20-60 min after the onset of reperfusion in hypothermic rats, although not thereafter (P < 0.05). Mild hypothermia speeds metabolic recovery temporarily during reperfusion but does not retard energy failure during global ischemia in rats.
AB - To record brain temperature for comparison with rectal and temporalis muscle temperatures in preliminary studies before MR spectroscopy experiments, a thermistor was inserted into the basal ganglia in eight anesthetized, ventilated, and physiologically monitored rats. The rats were placed in an MR spectrometer and subjected to 60 min of global cerebral ischemia and 2 h of reperfusion without radiofrequency (RF) pulsing. Body temperature was maintained at 37.5-38.0°C (normothermia) or 36.5-37.0°C (mild hypothermia). Brain temperature during ischemia, which dropped to 31.9 ± 0.3 (hypothermia) and 33.6 ± 0.5°C (normothermia), correlated with temporalis muscle temperature (r2 = 0.92) but not with body or magnet bore temperature measurements. Ischemia reduced brain temperature approximately 1.7°C in rats subjected to mild hypothermia (1°reduction of body temperature). Parallel MR spectroscopy experiments showed no significant difference in energy metabolites between normothermic and hypothermic rats during ischemia. However, the metabolic recovery was more extensive 20-60 min after the onset of reperfusion in hypothermic rats, although not thereafter (P < 0.05). Mild hypothermia speeds metabolic recovery temporarily during reperfusion but does not retard energy failure during global ischemia in rats.
KW - Cerebral ischemia
KW - Energy metabolism
KW - Hypothermia
KW - Magnetic resonance spectroscopy
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U2 - 10.1002/mrm.1910370606
DO - 10.1002/mrm.1910370606
M3 - Article
C2 - 9178233
AN - SCOPUS:0030926465
VL - 37
SP - 833
EP - 839
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 6
ER -