Objective:To study the effects of hyperbaric oxygen(HBO) on the levels of cerebral mitochondrial adenosine triphosphate (ATP) and proton-translocating ATP synthases(F 0F 1-ATPase) after brain ischemia/reperfusion (IR) in rats.Methods:Thirty Wistar rats were randomly divided into 3 groups:normal contorl group (n=6)

IR group (n=12) and HBO group ( n=12 ).IR was performed by ligation of the middle cerebral artery for 2 hours (hs) and then reperfusion in both the IR and HBO groups.The IR group was subdivided into group I 2h R 2h and group I 2h R 24h .The HBO group was subdivided into group HBO-I 2h R 2h and group HBO-I 2h R 24h .The IR group was treated by 2.5 ATAO 2.The HBO group was treated by 2.5 ATA O 2.The pure mitochondria was separated by Clak’s Ficoll density gradient method.The activity of F 0F 1-ATPase was determined by biochemical technigue and the level of cerebral ATP by high-performance liquid chromatography (HPLC).Results:The level of ATP and the activity of F 0F 1-ATPase increased after HBO treatment.In the IR group

the level of ATP and the activity of F 0F 1-ATPase were significantly lower than those of the HBO group( P <0.01).Conclusion:HBO improves mitochondrial oxygen metabolism

alleviates cerebral ischemic injury and protects brain tissues by means of recovering the activity of F 0F 1-ATPase and increasing the synthesis of ATP.