Artikel
Spreading depression triggers ictalform activity in disinhibited neuronal tissues
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Veröffentlicht: | 21. Mai 2013 |
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Gliederung
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Objective: Spreading depression (SD) belongs to the domain of the pathophysiology of the brain and has been linked to various neurological disorders, including migraine with aura, cerebrovascular diseases, head injury, transient global amnesia, and epilepsy. The close kinship between SD and experimental epileptic activity stimulated extensive investigation into the mutual relationship of these two phenomena. The aim of present study was to investigate the basic cellular mechanism of SD triggering epileptiform potentials (EFP) in partially disinhibited brain slices.
Method: Intracellular recordings were performed in the neocortex, hippocampus and amygdala after perfusion of sub-threshold of GABAA antagonist bicuculline. Induction of SD in combined amygdala-hippocampus-cortex slices pre-treated with sub-threshold concentration of GABAA antagonist bicuculline triggered ictal activities in cortical as well as subcortical brain structures.
Results: Propagation of SD significantly depolarised the membrane, decreased the neuronal membrane input resistance, and threshold potentials. Both the amplitude and duration of action potentials also reduced and the frequency of that enhanced after induction of SD. In addition, propagation of SD decreased the amplitude and duration of after hyperpolarisation.
Conclusions: The data indicate that a partial reduction of inhibitory tone by application of a GABAA antagonist promotes triggering of EFP by SD. This may important in occurrence of seizure attacks in neurological disorders in which brain suffers from partial impairment of inhibitory ton, such as brain ischemia and epilepsy.