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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-1-21
pubmed:abstractText
We investigated the potential of 4-AP (50-100 microM) to induce seizure-like events (SLEs) in combined entorhinal cortex-hippocampal slices from Sprague Dawley rats which developed spontaneous limbic seizures following kainic acid induced status epilepticus. Slices from control rats (n=8) displayed SLEs in the entorhinal and perirhinal cortex upon application of 50 or 100 microM 4-AP. By contrast, 4-AP failed to induce SLEs in slices from chronic epileptic rats (n=13) except for one slice from one rat. This animal displayed only minor cell loss in layer III of the entorhinal cortex, in contrast to the other epileptic rats for which layer III neuronal loss was extensive. In all slices from epileptic rats, 4-AP induced recurrent epileptiform discharges similar to the interictal activity observed in control rats. Combined application of 4-AP (100 microM) and bicuculline methiodide (30 microM) induced frequent and prolonged recurrent epileptiform discharges in both control and chronic epileptic rats. 4-AP at 50-100 microM likely affects potassium channels containing Kv1.4, Kv1.5, Kv3.1 or Kv3.2 subunits. Real-time PCR revealed no significant downregulation of Kv1.4, Kv1.5, Kv3.1 or Kv3.2 in the subiculum, entorhinal and perirhinal cortex from chronic epileptic rats compared to controls. However, the expression of Kv3.4, responding to 4-AP in mM range, was significantly reduced. Using sub-unit-specific antibodies, the real-time PCR findings were confirmed by immunocytochemistry. We suggest that after chronic epilepsy, reorganization in the entorhinal cortex is accompanied by adaptations in homeostatic plasticity with anticonvulsant consequences.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0969-9961
pubmed:author
pubmed:issnType
Print
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
186-200
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Reduced ictogenic potential of 4-aminopyridine in the perirhinal and entorhinal cortex of kainate-treated chronic epileptic rats.
pubmed:affiliation
Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Humboldt Universität, Tucholskystr. 2, D-10117 Berlin, Germany.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't