Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors
It is well established that impaired GABAergic inhibition within neuronal networks can lead to hypersynchronous firing patterns that are the typical cellular hallmark of convulsive epileptic seizures. However, recent findings have highlighted that a pathological enhancement of GABAergic signalling w...
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| Format: | Article |
| Language: | English |
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Wiley
2011-01-01
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| Series: | Advances in Pharmacological Sciences |
| Online Access: | http://dx.doi.org/10.1155/2011/790590 |
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| author | Adam C. Errington David W. Cope Vincenzo Crunelli |
| author_facet | Adam C. Errington David W. Cope Vincenzo Crunelli |
| author_sort | Adam C. Errington |
| collection | DOAJ |
| description | It is well established that impaired GABAergic inhibition within neuronal networks can lead to hypersynchronous firing patterns that are the typical cellular hallmark of convulsive epileptic seizures. However, recent findings have highlighted that a pathological enhancement of GABAergic signalling within thalamocortical circuits is a necessary and sufficient condition for nonconvulsive typical absence seizure genesis. In particular, increased activation of extrasynaptic GABAA receptors (eGABAAR) and augmented “tonic” GABAA inhibition in thalamocortical neurons have been demonstrated across a range of genetic and pharmacological models of absence epilepsy. Moreover, evidence from monogenic mouse models (stargazer/lethargic) and the polygenic Genetic Absence Epilepsy Rats from Strasbourg (GAERS) indicate that the mechanism underlying eGABAAR gain of function is nonneuronal in nature and results from a deficiency in astrocytic GABA uptake through the GAT-1 transporter. These results challenge the existing theory that typical absence seizures are underpinned by a widespread loss of GABAergic function in thalamocortical circuits and illustrate a vital role for astrocytes in the pathology of typical absence epilepsy. Moreover, they explain why pharmacological agents that enhance GABA receptor function can initiate or exacerbate absence seizures and suggest a potential therapeutic role for inverse agonists at eGABAARs in absence epilepsy. |
| format | Article |
| id | doaj-art-42b63e1ebe5d47dd861af64aa48c6f51 |
| institution | Kabale University |
| issn | 1687-6334 1687-6342 |
| language | English |
| publishDate | 2011-01-01 |
| publisher | Wiley |
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| series | Advances in Pharmacological Sciences |
| spelling | doaj-art-42b63e1ebe5d47dd861af64aa48c6f512025-02-03T06:12:28ZengWileyAdvances in Pharmacological Sciences1687-63341687-63422011-01-01201110.1155/2011/790590790590Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA ReceptorsAdam C. Errington0David W. Cope1Vincenzo Crunelli2School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UKSchool of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UKSchool of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UKIt is well established that impaired GABAergic inhibition within neuronal networks can lead to hypersynchronous firing patterns that are the typical cellular hallmark of convulsive epileptic seizures. However, recent findings have highlighted that a pathological enhancement of GABAergic signalling within thalamocortical circuits is a necessary and sufficient condition for nonconvulsive typical absence seizure genesis. In particular, increased activation of extrasynaptic GABAA receptors (eGABAAR) and augmented “tonic” GABAA inhibition in thalamocortical neurons have been demonstrated across a range of genetic and pharmacological models of absence epilepsy. Moreover, evidence from monogenic mouse models (stargazer/lethargic) and the polygenic Genetic Absence Epilepsy Rats from Strasbourg (GAERS) indicate that the mechanism underlying eGABAAR gain of function is nonneuronal in nature and results from a deficiency in astrocytic GABA uptake through the GAT-1 transporter. These results challenge the existing theory that typical absence seizures are underpinned by a widespread loss of GABAergic function in thalamocortical circuits and illustrate a vital role for astrocytes in the pathology of typical absence epilepsy. Moreover, they explain why pharmacological agents that enhance GABA receptor function can initiate or exacerbate absence seizures and suggest a potential therapeutic role for inverse agonists at eGABAARs in absence epilepsy.http://dx.doi.org/10.1155/2011/790590 |
| spellingShingle | Adam C. Errington David W. Cope Vincenzo Crunelli Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors Advances in Pharmacological Sciences |
| title | Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors |
| title_full | Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors |
| title_fullStr | Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors |
| title_full_unstemmed | Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors |
| title_short | Augmentation of Tonic GABAA Inhibition in Absence Epilepsy: Therapeutic Value of Inverse Agonists at Extrasynaptic GABAA Receptors |
| title_sort | augmentation of tonic gabaa inhibition in absence epilepsy therapeutic value of inverse agonists at extrasynaptic gabaa receptors |
| url | http://dx.doi.org/10.1155/2011/790590 |
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