| Desynchronisation of spontaneously recurrent experimental seizures proceeds with a single rhythm. | |
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MedLine Citation:
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PMID: 14568030 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Here we investigate the temporal properties of recurrent seizure-like events (SLEs) in a low-[Mg(2+)] model of experimental epilepsy. Simultaneous intra- and extracellular electric signals were recorded in the CA3 region of rat hippocampal slices whereby cytosolic [Ca(2+)] transients were imaged by fluorescence detection. Recurrence pattern analysis was applied to give a measure of synchrony of simultaneously recorded intra- and extracellular electric signals and the SLE frequencies were extracted by complex wavelet analysis. Slices from the juvenile, but not the young adult rats, displayed several high-amplitude triplets of electric and [Ca(2+)] transients, termed paroxysmal spikes, followed by an SLE. Occurrence of the full-blown SLE was associated with decreased synaptic activity between the paroxysmal spikes that were seen as incomplete SLE starting sequences. The time series of recurrent SLEs provide evidence for a single SLE rhythm as continuously declining from about 200 Hz to below 1 Hz at the onset and termination of SLE, respectively, with an intermediate spectral discontinuity, tentatively identified with the tonic/clonic transition. All other frequency components were the harmonics of the fundamental rhythm, whereby the gamma and the theta band oscillations were not detected as separate activities. Recurrence showed decreasing temporal synchrony of intra- and extracellular signals during the SLE, suggesting that coincidence is destroyed by the SLE. Blockade of gap junctions with 200 microM carbenoxolone ceased recurrent SLEs. Release of gap junction blockade shortened both SLEs and their tonic phase indicating that persistent changes occurred via an altered gap junction coupling. We conclude that the initially precise temporal synchrony is gradually destroyed during ictal events with a single rhythm of continuously decreasing frequency. Blockade of gap junction coupling might prevent epileptic synchronisation. |
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Authors:
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L Nyikos; B Lasztóczi; K Antal; R Kovács; J Kardos |
Publication Detail:
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Type: Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Neuroscience Volume: 121 ISSN: 0306-4522 ISO Abbreviation: Neuroscience Publication Date: 2003 |
Date Detail:
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Created Date: 2003-10-21 Completed Date: 2004-01-09 Revised Date: 2009-11-03 |
Medline Journal Info:
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Nlm Unique ID: 7605074 Medline TA: Neuroscience Country: United States |
Other Details:
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Languages: eng Pagination: 705-17 Citation Subset: IM |
Affiliation:
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Department of Neurochemistry, Chemical Institute, Chemical Research Center, Hungarian Academy of Sciences, Budapest, Hungary. nyikos@chemres.hu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Animals, Newborn Anti-Ulcer Agents / pharmacology, therapeutic use Calcium / metabolism Carbenoxolone / pharmacology, therapeutic use Cortical Synchronization* Disease Models, Animal Evoked Potentials Fluorometry Hippocampus / drug effects, physiopathology* Magnesium / metabolism Male Membrane Potentials Patch-Clamp Techniques Rats Rats, Wistar Seizures / drug therapy, physiopathology* Time Factors |
| Chemical | |
Reg. No./Substance:
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0/Anti-Ulcer Agents; 5697-56-3/Carbenoxolone; 7439-95-4/Magnesium; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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