Effect of changing potassium ion concentrations on rat cerebral slices in vitro: a study during development

Adult rat cerebral cortex slices when incubated in media in increasing K+ concentrations, from 3 to 20 mM ("physiological" conditions), exhibited an increase of Ki+ and a decrease of Nai+ and Cli-. This phenomenon appeared at 30 days postnatally, which is fairly late during development. Over 20 mM-K+ ("pathological" conditions) an intense water uptake was observed together with an increase of Nai+ and Cli-. This was observed in both adult and young animals. The results are discussed in relation to the well known properties of glial (Na+,K+)-ATPase and carbonic anhydrase.