Studies of the production and subsequent reduction swelling in primate. Cerebral cortex under isosmotic conditions in vivo.

Abstract

1. The swelling of intact primate cerebral cortex perfused under isosmotic conditionsin vivo, like swelling of slices of mammalian cerebral cortex incubatedin vitro, is a linear function of the concentration of K+ in the extracellular fluid over the range 20–120 mM. 2. The simultaneous presence of the Cl− ion is required for the development of K+-dependent swelling of cerebral cortex under various experimental conditionsin vivo andin vitro. 3. The maintenance of previously established K+-dependent swelling of cerebral cortex bothin vitro andin vivo requires the relative concentrations of both K+ and Cl− in the extracellular fluid to remain constant. A reduction in the concentration of either ion is associated with an absolute loss of fluid of swelling of cerebral cortex. 4. The content of Cl− in cerebral cortex is a function of the magnitude of K+-dependent swelling even though the concentration of Cl− in the extracellular fluid is maintained constant. 5. The mechanism of swelling in primate cerebral cortex following cerebral circulatory arrest is discussed in the light of the experimental findings, as a model of the type of brain injury encountered in massive clinical stroke.