[Relations between the cortical DC potentials and the K+ concentration of the blood and cerebral cortex extracellular space in reversible asphyxia].
The relationship between changes of the cortical DC potential and the K+ concentration gradient across the blood-brain barrier (BBB) was studied in the rat brain during short ventilatory arrest. For this purpose K+ concentrations were measured simultaneously in the extracellular space of the cerebral cortex and in the streaming blood of the carotid artery and the superior sagittal sinus. For measurements ion-selective micro- and macro-electrodes based on the K+ ionophore valinomycin were used. During reversible asphyxia free K+ concentrations in the circulating blood and in the extracellular fluid of the brain tissue increased and re-decreased with different time courses. The resulting difference between the electromotive forces of the ion-selective signals resembled the course of the cortical DC potential during the initial phase of the ventilatory arrest during the post-asphyxiation period. The results suggest that during these events the cortical tissue including the BBB behaves like a K+-selective membrane which is probably located at the blood-brain interface. It is concluded that the capillary-glial complex may principally contribute to the generation of DC shifts associated with the asphyxiation process.
D000818:Animals; D001237:Asphyxia / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D004594:Electrophysiology; D005110:Extracellular Space / Q000032:analysis*; D007477:Ions; D011188:Potassium / Q000032:analysis* / Q000097:blood; D051381:Rats
D007477:Ions; D011188:Potassium
Beziehungen zwischen kortikalen DC Potentialen und der K+-Konzentration im Blut und Extrazellulärraum der Hirnrinde bei reversibler Asphyxie.