The Effect of Ketamine Anesthesia on the Formation of Brain Edema During Focal Ischemia in Rats

ABSTRACT

Excitatory amino acids have been implicated as one of the important putative cellular toxins in ischemic brain. Ketamine antagonizes the excitotoxic action of excitatory amino acids in the central nervous system. The present study was undertaken to determine whether ketamine anesthesia protect the formation of brain edema in the model of focal cerebral ischemia in rats. Forty adult male Sprague-Dawley rats weighing between 300gm and 400gm were used in this study. The animals were anesthetized with either halothane or ketamine, and then right middle cerebral artery occlusion were performed. After 4 hours of ischemia, the brain water and ion contents(Na+ and K+) were determined in the central, intermediate, and outer zones of each cortical mantle. In both halothane and ketamine anesthetized groups, there were significant brain edema in the ischemic central and intermediate zones. Ionic shifts were also observed in the ischemic central and intermediate zones to approximately same extent as the brain water content in both groups. However, there were no significant differences of brain edema between the two groups in the corresponding ischemic zones. These results suggest that ketamine anesthesia does not have significant protective effect on the formation of brain edema during the early stages of permanent incomplete cerebral ischemia.