Functional and morphological changes in the hippocampal neuronal circuits associated with epileptic seizures
| Autor: | Masutaro Kanda, Hiroshi Ashida, Eiichi Maru |
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| Rok vydání: | 2002 |
| Předmět: |
Time Factors
Long-Term Potentiation Hippocampal formation Hippocampus Synaptic Transmission Epilepsy Seizures Convulsion medicine Kindling Neurologic Animals Humans Ictal gamma-Aminobutyric Acid Neuronal Plasticity Kindling Dentate gyrus Excitatory Postsynaptic Potentials Long-term potentiation medicine.disease Receptors GABA-A Rats Electrophysiology Disease Models Animal Neurology Dentate Gyrus Mossy Fibers Hippocampal GABAergic Regression Analysis Neurology (clinical) medicine.symptom Psychology Neuroscience |
| Zdroj: | Epilepsia. 43 |
| ISSN: | 0013-9580 |
| Popis: | Summary: Purpose: We review what is currently known about functional and morphologic plasticity of hippocampal neuronal circuits in animal epilepsy models. Results: Perforant-path kindling has been shown to enhance excitatory synaptic transmission in the dentate gyrus significantly, and this enhancement has lasted for ≥1 month after kindling. However, in our rapid kindling experiment with an interstimulus interval of 5 min, perforant-path kindling resulted in behavioral convulsions and prolonged the afterdischarge duration, but dentate synaptic transmission remained depressed during kindling. Conclusions: These results indicate that kindling-induced synaptic potentiation is not necessary for kindling development. Conversely, epileptic seizures have led to the anomalous sprouting of mossy fibers, a process thought to induce hyperexcitation of granule cells. We conclude that the sprouting of mossy fibers did not play a critical role in kindling, because we observed no significant correlation between the mossy fiber sprouting and kindling development. Epileptic seizures also have been shown to increase γ-aminobutyric acid (GABA)A receptor–mediated inhibition during interictal periods. Although this strengthening of GABAergic inhibition is likely to be a defensive measure against seizure initiation, some studies have suggested that another type of GABAergic response facilitates seizure activity. The possibility of GABAA receptor–mediated excitation during ictal periods is theoretically examined. |
| Databáze: | OpenAIRE |
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