ACTIVITY OF MITOCHONDRIAL RESPIRATORY-CHAIN ENZYMES AFTER TRANSIENT FOCAL ISCHEMIA IN THE RAT

Previous results demonstrated that after 2-hour middle cerebral artery occlusion (MCAO) in the rat, 1- to 2-hour recirculation temporarily r estored the bioenergetic state and mitochondrial function, but seconda ry deterioration took place after 4 hours. The authors measured the ac tivity of mitochondrial respiratory chain complexes, citrate synthase, and glutamate dehydrogenase as possible targets of secondary damage. Focal and penumbral tissues were sampled in the control condition, aft er 2 hours of MCAO, and after 1, 2, or 4 hours of postischemic recircu lation; two groups were treated with alpha-phenyl-N-tert-butyl-nitrone (PBN). Complex IV activity transiently decreased after MCAO, but afte r recirculation all measured activities returned to control values.