Cell swelling precedes seizures induced by inhibition of astrocytic metabolism.

It is currently unknown what processes take place at the interface between non-ictal and ictal activity during seizure initiation. In this study, using paralysed awake rats, we focally inhibited astrocytic metabolism with fluorocitrate (FC), causing seizures. We measured changes in electroencephalogram (EEG) (0-300 Hz), and extracellular ion-concentrations during ictal onsets defining possible relationships with impedance-determined cell swelling. In animals showing ictal activity (69%) there were spike-wave discharges, spike-wave discharges followed by spreading depression and spreading depression without any discharges. In a high proportion of spike-wave discharges (>95%), just prior to the first spike-wave discharge, there was a decrease in the volume of the extracellular space. Following the initiation of cell swelling and prior to discharges, there were increases in high-frequency (150-300 Hz) EEG activity, increases in extracellular potassium- and decreases in extracellular calcium-concentrations. We suggest that EEG and ionic changes are not causative of cell swelling. Cell swelling due to metabolic failure in astrocytes at the injected site may release excitatory amino acids. At the same time, our results suggest ion homeostasis is not maintained and increased neuronal excitability and synchronisation occur. These could be the drivers changing normal brain activity into ictal activity.

Pope, KennethFlinders University of South Australia (author)
Lewis, TFlinders University of South Australia (author)
Olsson, Torsten,1937Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)torsten (author)
Nilsson, Michael,1962Gothenburg University,Göteborgs universitet,Institutionen för neurovetenskap och fysiologi, sektionen för klinisk neurovetenskap och rehabilitering,Institute of Neuroscience and Physiology, Department of Clinical Neuroscience and Rehabilitation,University of Gothenburg(Swepub:gu)xnimic (author)
Willoughby, JohnFlinders University of South Australia (author)
Flinders University of South AustraliaChalmers tekniska högskola (creator_code:org_t)

By the author/editor: Broberg, Marita, ...; Pope, Kenneth; Lewis, T; Olsson, Torsten, ...; Nilsson, Michael ...; Willoughby, John

About the subject

MEDICAL AND HEALTH SCIENCES: MEDICAL AND HEAL ...; and Clinical Medicin ...; and Neurology

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Medical Engineer ...; and Medical Laborato ...

By the university: University of Gothenburg; Chalmers University of Technology

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