Unaltered cerebral Na+,K+-ATPase activity after hypoxic/ischemic injury in piglets.

We examined whether hypoxic/ischemic (H/I) stress decreased the cerebral Na(+),K(+)-ATPase enzyme activity (NEA) of newborn pigs. The effects of global ischemia (10 min), asphyxia (10 min), and incomplete forebrain ischemia (45 min) were analyzed in ten different brain regions. The lengths of the reperfusion periods varied between 15 min and 3 h. NEA was determined as the ouabain-sensitive fraction of the total ATPase activity of the sample. Marked regional differences in NEA were observed in all experimental groups, whereas NEA was not significantly affected in any of the brain structures investigated. The present results suggest that damaged brain Na(+),K(+)-ATPase may not be the cause of the neuronal-vascular impairment following H/I stress.