Extracellular potassium concentration changes during propagated seizures in neocortex

• Published in: Experimental neurology Vol. 38; no. 1; pp. 20 - 26
• Main Authors: Hotson, J.R., Sypert, G.W., Ward, A.A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 1973
• Subjects: Animals; Cats; Cerebral Cortex - metabolism; Electroencephalography; Membrane Potentials; Microelectrodes; Neuroglia - metabolism; Potassium - metabolism; Seizures - metabolism
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/0014-4886(73)90004-6

Cortical surface and intracortical, extracellular K + selective microelectrode recording was carried out in the pericruciate cortex of cats during propagated seizures produced by repetitive stimulation of the surface of the contralateral homotopic neocortex. The K + selective microelectrode consistently recorded a potential change which corresponded to an increase in [K +] 0 which was directly related to the seizure amplitude × duration. The interictal [K +] 0 in neocortical extracellular fluid was determined to be 4 meq/liter. The maximum increase of [K +] 0 during propagated seizures in these experiments was 7 meq/liter which correlates lates well with increases in [K +] 0 calculated from neuroglial depolarizations during similar propagated seizures.