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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
4
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pubmed:dateCreated |
2002-10-7
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pubmed:abstractText |
Inhibitory GABAergic signalling in the hippocampus plays an important role in synchronizing principal cells and regulating the excitability of this seizure-prone structure. Distinct mechanisms modulate release from GABAergic terminals in the hippocampus, depending on whether the postsynaptic partner is an interneuron or a principal cell. Here, we report that postsynaptic ionotropic GABA receptors in principal cells and interneurons also show a striking pharmacological difference. The broad-spectrum antagonist picrotoxin (PTX) was less potent at blocking IPSCs evoked in stratum radiatum interneurons than in pyramidal neurons in the CA1 region. GABA-evoked currents in membrane patches from interneurons showed a smaller mean unitary conductance than in patches from pyramidal neurons. Because retinal GABA(C) receptors show decreased picrotoxin sensitivity and conductance, we examined the effect of the GABA(C) receptor agonist cis-aminocrotonic acid (CACA). Although this agent evoked picrotoxin-resistant currents in interneurons, these were enhanced by the GABA(A) allosteric modulator pentobarbital. Moreover, both picrotoxin-resistant IPSCs and CACA-evoked currents were blocked by the GABA(A) receptor-selective antagonist bicuculline. The presence of relatively picrotoxin-resistant GABA(A) receptors in interneurons provides a potential target for agents to modulate the activity of sub-populations of hippocampal neurons.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Bicuculline,
http://linkedlifedata.com/resource/pubmed/chemical/GABA Agonists,
http://linkedlifedata.com/resource/pubmed/chemical/GABA Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/GABA Modulators,
http://linkedlifedata.com/resource/pubmed/chemical/GABA-C receptor,
http://linkedlifedata.com/resource/pubmed/chemical/Pentobarbital,
http://linkedlifedata.com/resource/pubmed/chemical/Picrotoxin,
http://linkedlifedata.com/resource/pubmed/chemical/Pyridines,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, GABA,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, GABA-A,
http://linkedlifedata.com/resource/pubmed/chemical/gamma-Aminobutyric Acid,
http://linkedlifedata.com/resource/pubmed/chemical/zolpidem
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pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0028-3908
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
43
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
726-36
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:12367618-Animals,
pubmed-meshheading:12367618-Bicuculline,
pubmed-meshheading:12367618-Electrophysiology,
pubmed-meshheading:12367618-Excitatory Postsynaptic Potentials,
pubmed-meshheading:12367618-GABA Agonists,
pubmed-meshheading:12367618-GABA Antagonists,
pubmed-meshheading:12367618-GABA Modulators,
pubmed-meshheading:12367618-Guinea Pigs,
pubmed-meshheading:12367618-Hippocampus,
pubmed-meshheading:12367618-Interneurons,
pubmed-meshheading:12367618-Iontophoresis,
pubmed-meshheading:12367618-Membrane Potentials,
pubmed-meshheading:12367618-Patch-Clamp Techniques,
pubmed-meshheading:12367618-Pentobarbital,
pubmed-meshheading:12367618-Picrotoxin,
pubmed-meshheading:12367618-Pyramidal Cells,
pubmed-meshheading:12367618-Pyridines,
pubmed-meshheading:12367618-Receptors, GABA,
pubmed-meshheading:12367618-Receptors, GABA-A,
pubmed-meshheading:12367618-gamma-Aminobutyric Acid
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pubmed:year |
2002
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pubmed:articleTitle |
Relative picrotoxin insensitivity distinguishes ionotropic GABA receptor-mediated IPSCs in hippocampal interneurons.
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pubmed:affiliation |
University College London, Institute of Neurology, Queen Square, UK.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
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