Abstract

• Objectives
  The purpose of this study is to investigate e effects of preischemic hyperglycemia on e alterations of'adenosine triphosphate and lactate concentrations in e acutefocal ischernic brain of the cats.
• Methods
  Acute focal cerebral ischemia in cats was induced by occlusion of the left middlecerebral artery through the postorbital technique. The experimental animals were divided into 3 goups: sham control, occlusion and recirculation groups. Each group was divided into 2 subgroups: normoglycemic and hyperglycemic groups.
• Results
  The experimental results are obtained as fo11ows;
  1) In normoglycemic subgroups of occlusion and recirculation proups, amount of adenosinetriphosphate in ischmic brain decreased significantly to 3.0% and 13.0% of the sham control,respectively(p < 0.001).
  In hyperglycemic subgroups of occlusion and recirculation groups, amount of adenosine trisphosphate decreased a little more an at in normoglycemic subgroups, even so there wasno statistic significancy(p > 0.1).
  2) In normoglycemic subgroups of occlusion and recirculation groups, amount of lactate inischemic brain increased signigicantly to 175.7% and 187.9% of the sham control, respectively(p < 0.001).
  In hyperglycemic subgroups of occlusion and recirculation groups, amount of lactate increased nore than that in normoglycemic subgroups with statistic significancy(0.001 < p < 0.01).
• Conclusion
  These results suggest that hyperglycemia before ischemia serves to elevate glucose transport into brain tissue and thereby, to promote profound tissue acidosis throughanaerobic glycolysis caused by a failure of adenosine triphosphate stnthesis during the ischemicperiod.
• Keywords: Acute focal cerebral ischemia; ATP; Lactate; Hyperglycemia