Stimulus-induced changes in extracellular Na+ and Cl- concentration in relation to changes in the size of the extracellular space

摘要: Extracellular Na+- and Cl−-concentrations ([Na+]o, [Cl−]o) were recorded with ion-selective microelectrodes during repetitive stimulation stimulus-induced self-sustained neuronal afterdischarges (SAD) in the sensorimotor cortex of cats. In all cortical layers [Na+]o initially decreased by 4–7 mM. depths more than 600 μm below surface such decreases usually turned into increases 2–6 mM course SADs, whereas superficial never rose above its resting level. [Cl−]o always showed an increase SADs often preceded initial small decrease. The average at a depth 1,000 was about 7 reached peak values end ictal period, maximum shortly after SAD, times when [K+]o still elevated baseline concentration.