CHANGES OF LOCAL CEREBRAL GLUCOSE UTILIZATION, DC POTENTIAL AND EXTRACELLULAR POTASSIUM IN VARIOUS DEGREE OF EXPERIMENTAL CEREBRAL CONTUSION Motoo Kubota 1 , Takao Nakamura 1 , Kenro Sunami 1 , Yoshinori Ozawa 1 , Hiroki Namba 1 , Akira Yamaura 1 , Hiroyasu Makino 1 1Department of Neurological Surgery, School of Medicine, Chiba University pp.799-805
Published Date 1989/8/1
DOI https://doi.org/10.11477/mf.1406206369
  • Abstract
  • Look Inside

Pathophysiology of the traumatized brain, espe-cially that of cerebral contusion, is very complex and has not been well understood. In recent years, changes in extracellular ion concentration have been known in various pathological conditions such as cerebral concussion, spinal contusion, ischemia, hypoglycemia, epilepsy and spreading depression as one of the triggers to lead to secondary brain damage. To know the metabolic and ionic chan-ges following cerebral contusion, the authors made various degree of cerebral contusion by fluid per-cussion method, and observed successive changes in EEG, DC potential, extracellular potassium con-centration and local cerebral glucose utilization (LCGU).

Materials and Methods: Using 42 male Wistar rats, mild (0. 2 kg/cm2), moderate (0. 4 kg/cm2) and severe contusion (0. 6 kg/cm') were made in the left lower parietal region of the rats. EEG, DC poten-tial and extracellular potassium concentration (us-ing potassium sensitive glass microelectrode) were monitored for four to five hours after making the contusions. LCGU (by '4C-2-deoxyglucose method) was studied at the time of the negative shift of DC potential.

Results: The negative shift of DC potential with EEG supression was observed at 30 min. to 3 hours after injury. The severer the injury was, the earli-er and the more frequent negative shifts appear-ed. LCGU showed no significant changes in the mild injury group. In the moderate injury group, frequent negative shifts of DC potential associated with EEG supression were observed. A 20% in-crease of glucose utilization in the cortex of thelesion side was observed whereas 50% decreases in the subcortical structures were found. In the severe injury group, EEG was supressed immedia-tely after contusion and had never recovered. DC potential fluctuated and was unstable. The increase of LCGU was noted not only in the cortex of the lesion side but also in some of the subcortical structures (hippocampus, caudate nucleus, dentate nucleus and thalamus). The extracellular potassium concentration rose to 30 mM, being correlatedclosely with DC potential.

Discussion : Increase of LCGU associated with EEG supression, negative shift of DC potential and elevation in extracellular potassium concentration was thought to be due to spreading depression. It was postulated that spreading depression following cerebral contusion causes energy failure and can lead to secondary brain damage.

Copyright © 1989, Igaku-Shoin Ltd. All rights reserved.


電子版ISSN 2185-405X 印刷版ISSN 0006-8969 医学書院