ABSTRACT
The author studied the effect of the recirculation on the energy metabolism in acute focal cerebral ischemia. Acute focal cerebral ischemia was produced by transorbital occlusion of the left middle cerebral artery with a Heifetz clip under the operating microscope. The animals were divided into three groups according to the duration of the ischemia. Each group was reperfused for 1, 4 and 7 hour by removing the clip from the artery. In 1-hour ischemic group ATP and GTP was reduced to 38% and IMP to 40% of the sham control. After 7-hour recirculation in this group ATP was resynthesized to 85%, GTP to 85%, and IMP to 180% of the sham control. In 3-hour ischemic group ATP was reduced to 19%, GTP to 23%, and IMP to 29% of the sham control. In this group ATP, GTP and IMP rose to 43%, 49% and 84%, respectively after 7-hour recirculation ATP, GTP and IMP were markedly reduced in 5-hour ischemic group, and despite recirculation these substances continued to decrease and none of them were detected after 7-hours of recirculation, It was suggested that the restoration of the circulation must be accomplished within 1-hour or at least within 3-hour of the ischemic insult of the cats to prevent the irreversible brain infarction.