Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy
Mesial temporal lobe epilepsy patients often display shrinkage of the entorhinal cortex, which has been attributed to neuronal loss in medial entorhinal cortex layer III (MEC-III). MEC-III neuronal loss is reproduced in chronic epileptic rats after kainate-induced (KA) status epilepticus. Here we ex...
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| Format: | Article |
| Language: | English |
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Elsevier
2007-05-01
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| Series: | Neurobiology of Disease |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0969996107000290 |
| _version_ | 1818648736653377536 |
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| author | Else A. Tolner Christiane Frahm Robert Metzger Jan A. Gorter Otto W. Witte Fernando H. Lopes da Silva Uwe Heinemann |
| author_facet | Else A. Tolner Christiane Frahm Robert Metzger Jan A. Gorter Otto W. Witte Fernando H. Lopes da Silva Uwe Heinemann |
| author_sort | Else A. Tolner |
| collection | DOAJ |
| description | Mesial temporal lobe epilepsy patients often display shrinkage of the entorhinal cortex, which has been attributed to neuronal loss in medial entorhinal cortex layer III (MEC-III). MEC-III neuronal loss is reproduced in chronic epileptic rats after kainate-induced (KA) status epilepticus. Here we examined, in vitro, functional changes in superficial entorhinal cortex layers. Alterations in superficial layer circuitry were suggested by showing that presubiculum, parasubiculum and deep MEC stimulation evoked 100–300 Hz field potential transients and prolonged EPSPs (superimposed on IPSPs) in superficial MEC which were partially blocked by APV (in contrast to control) and fully blocked by CNQX. Contrary to controls, bicuculline (5 and 30 μM) had minor effects on evoked field potentials in KA rats. GAD65/67 in situ hybridization revealed preserved interneurons in MEC-III. In conclusion, hyperexcitability in superficial MEC neurons is not due to loss of GABAergic interneurons and probably results from alterations in synaptic connectivity within superficial MEC. |
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| id | doaj.art-b67d4fe89ea24379830e37b8c7831aec |
| institution | Directory Open Access Journal |
| issn | 1095-953X |
| language | English |
| last_indexed | 2024-12-17T01:23:10Z |
| publishDate | 2007-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Neurobiology of Disease |
| spelling | doaj.art-b67d4fe89ea24379830e37b8c7831aec2022-12-21T22:08:45ZengElsevierNeurobiology of Disease1095-953X2007-05-01262419438Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsyElse A. Tolner0Christiane Frahm1Robert Metzger2Jan A. Gorter3Otto W. Witte4Fernando H. Lopes da Silva5Uwe Heinemann6Johannes-Müller-Institute of Physiology at the Charité, Humboldt University Berlin, Tucholskystr. 2, 10117 Berlin, Germany; Corresponding author. Dept. of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), 00014 Helsinki, Finland. Fax: +358 9 19159810.Department of Neurology, Friedrich-Schiller-University, Erlanger Allee 101, 07745 Jena, GermanyJohannes-Müller-Institute of Physiology at the Charité, Humboldt University Berlin, Tucholskystr. 2, 10117 Berlin, GermanySwammerdam Institute of Life Sciences, Section of Neurobiology, University of Amsterdam, Graduate School of Neurosciences Amsterdam, NL-1098 SM, Amsterdam, The NetherlandsDepartment of Neurology, Friedrich-Schiller-University, Erlanger Allee 101, 07745 Jena, GermanySwammerdam Institute of Life Sciences, Section of Neurobiology, University of Amsterdam, Graduate School of Neurosciences Amsterdam, NL-1098 SM, Amsterdam, The NetherlandsJohannes-Müller-Institute of Physiology at the Charité, Humboldt University Berlin, Tucholskystr. 2, 10117 Berlin, GermanyMesial temporal lobe epilepsy patients often display shrinkage of the entorhinal cortex, which has been attributed to neuronal loss in medial entorhinal cortex layer III (MEC-III). MEC-III neuronal loss is reproduced in chronic epileptic rats after kainate-induced (KA) status epilepticus. Here we examined, in vitro, functional changes in superficial entorhinal cortex layers. Alterations in superficial layer circuitry were suggested by showing that presubiculum, parasubiculum and deep MEC stimulation evoked 100–300 Hz field potential transients and prolonged EPSPs (superimposed on IPSPs) in superficial MEC which were partially blocked by APV (in contrast to control) and fully blocked by CNQX. Contrary to controls, bicuculline (5 and 30 μM) had minor effects on evoked field potentials in KA rats. GAD65/67 in situ hybridization revealed preserved interneurons in MEC-III. In conclusion, hyperexcitability in superficial MEC neurons is not due to loss of GABAergic interneurons and probably results from alterations in synaptic connectivity within superficial MEC.http://www.sciencedirect.com/science/article/pii/S0969996107000290EpileptogenesisCell lossPresubiculumDisinhibitionGAD65/67-hyperexcitability |
| spellingShingle | Else A. Tolner Christiane Frahm Robert Metzger Jan A. Gorter Otto W. Witte Fernando H. Lopes da Silva Uwe Heinemann Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy Neurobiology of Disease Epileptogenesis Cell loss Presubiculum Disinhibition GAD65/67-hyperexcitability |
| title | Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy |
| title_full | Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy |
| title_fullStr | Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy |
| title_full_unstemmed | Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy |
| title_short | Synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate-induced epilepsy |
| title_sort | synaptic responses in superficial layers of medial entorhinal cortex from rats with kainate induced epilepsy |
| topic | Epileptogenesis Cell loss Presubiculum Disinhibition GAD65/67-hyperexcitability |
| url | http://www.sciencedirect.com/science/article/pii/S0969996107000290 |
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