Behavioral changes and local cerebral glucose utilization in septic rats

Behaviors, electroencephalogram (EEG) and local cerebral glucose utilization (LCGU) were evaluated in the septic rat model, produced by cecal ligation and punctures. Behaviors (ambulation, reading, grooming and preening) were observed in an open-field situation, and pain threshold was determined by a tail-flick method. In the sepsis group(25 rats), ambulation at four hours, rearing and grooming＋preening at two hours after the surgical procedure of sepsis were significantly depressed as compared to the sham operated control group(15 rats). Pain threshold significantly increased at the same time. LCGUs in the 28 brain regions were measured by a quantitative autoradiographic method using [^<14>C] -deoxyglucose in both sepsis and control groups. In septic rats, LCGUs were measured when behavioral depression and EEG slowing had been fully developed. The mean LCGUs in the sepsis group(7 rats) were lower by 14 to 27% than those in the sontrol group(7 rats) in locus coeruleus, hippocampal molecular layer, parietal and auditory cortices, lateral geniculate and superior colliculli, while they were significantly higher by 27 and 33% than those in the control group, in septal and raphe nuclei, respectively. These results suggesu that septic encephalopathy is closely related with the changes in serotonergic and noradrenergic systems in the brain.