Cell swelling, seizures and spreading depression: An impedance study
| Autor: | John O. Willoughby, I Marita Broberg, Lorraine Mackenzie, Torsten Olsson, Angus Wallace, Kenneth J. Pope, Fredrik Blomstrand, Michael Nilsson |
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| Rok vydání: | 2006 |
| Předmět: |
Male
Kainic acid Models Neurological Central nervous system Action Potentials Brain Edema Convulsants Electroencephalography Synaptic Transmission Membrane Potentials Rats Sprague-Dawley chemistry.chemical_compound Epilepsy Electric Impedance medicine Animals Cell Size Cerebral Cortex Neurons medicine.diagnostic_test business.industry General Neuroscience Cell Membrane Cortical Spreading Depression Neural Inhibition Water-Electrolyte Balance medicine.disease Rats nervous system diseases Disease Models Animal medicine.anatomical_structure nervous system chemistry Cerebral cortex Cortical spreading depression Anesthesia Convulsant business Picrotoxin |
| Zdroj: | Neuroscience. 140:505-515 |
| ISSN: | 0306-4522 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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