Cell Swelling, Seizures and Spreading Deprssion: An Impedance Study
Artikel i vetenskaplig tidskrift, 2006

The cellular processes that take place during the transition from pre-seizure state to seizure remain to be defined. In this study in awake, paralyzed rats, we used an electrical impedance measure of changes in extra-cellular intracranial volume to estimate changes in cell size in acute models of epilepsy. Animals were prepared with extradural electroencephalographic (EEG)/impedance electrodes and a venous catheter. On a subsequent day, animals were paralyzed, ventilated and treated with picrotoxin, kainic acid or fluorocitrate in doses that usually induce epileptiform discharges. We now report that increases in baseline impedance were induced by kainic acid and smaller increases by picrotoxin. We also demonstrated that epileptiform discharges were preceded by small, accelerated increases in impedance. Increases in baseline impedance were highly correlated with increases in power of non-ictal high frequency EEG activity. Seizures were accompanied by increases in impedance and all treatments induced transient, relatively large, increases in impedance often associated with unilateral reductions in low frequency EEG, likely periods of spreading depression. We conclude: cerebral cells swell in convulsant models of epilepsy, that there are pre-ictal accelerations in cell swelling, and that spreading depression-like events are frequently associated with seizures.

picrotoxin

rat

astroglia.

cerebral cortex

kainic acid

fluorocitrate

Författare

Torsten Olsson

Signaler och system, Signalbehandling och medicinsk teknik, Medicinska signaler och system

Marita Broberg

Göteborgs universitet

Kenneth Pope

Flinders University

Andrew Wallace

Flinders University

Lorraine Mackenzie

Flinders University

Fredrik Blomstrand

Göteborgs universitet

Michael Nilsson

Göteborgs universitet

John Willoughby

Flinders University

Neuroscience

0306-4522 (ISSN)

Vol. 140 505–515-

Ämneskategorier

Medicinsk laboratorie- och mätteknik

Fysiologi

DOI

10.1016/j.neuroscience.2006.02.034