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Role of gap junctions on synchronization in human neocortical networks
S Gigout1, R A Deisz2, C Dehnicke3
1INSERM U1129 Infantile Epilepsies and Brain Plasticity, Paris, France; University Paris Descartes, Paris, France; Charité Universitätsmedizin Berlin, Centre for Anatomy, Institute for Cell Biology and Neurobiology, Berlin, Germany.
Brain Research
|February 14, 2016
Summary
Glial gap junctions (GJ) influence the frequency of epileptic activity, while neuronal GJ control synchrony in specific cortical layers. This study clarifies their distinct roles in temporal lobe epilepsy.
Area of Science:
- Neuroscience
- Epilepsy Research
- Cellular Electrophysiology
Background:
- Gap junctions (GJ) are crucial for neuronal communication and implicated in epilepsy.
- Glial GJ were previously thought to regulate epileptiform activity frequency, and neuronal GJ synchrony.
- The precise roles of glial versus neuronal GJ in epileptogenesis remain to be fully elucidated.
Purpose of the Study:
- To investigate the role of glial GJ activator (GAP-134) on 4-aminopyrine (4AP)-induced epileptiform activity.
- To delineate the impact of GJ on the spatial spread of synchronous activity using carbenoxolone (CBX).
- To differentiate the functions of glial and neuronal GJ in human temporal lobe epilepsy tissue.
Main Methods:
- Utilized human neocortical slices from temporal lobe epilepsy patients.
- Administered 4-aminopyrine (4AP) to induce epileptiform activities.
- Applied GAP-134 (glial GJ activator) and carbenoxolone (CBX, non-selective GJ blocker) to assess effects on activity frequency and synchrony (PUI).
- Examined GJ effects across vertical and lateral cortical layers.
Main Results:
- GAP-134 slightly increased the frequency of 4AP-induced epileptiform activities without affecting synchrony (PUI).
- CBX did not alter PUI within cortical columns or in deep cortical layers.
- CBX increased PUI over longer distances specifically in the upper cortical layers.
Conclusions:
- Glial GJ play a role in maintaining the frequency of spontaneous epileptic activities.
- Neuronal GJ are responsible for controlling synchrony (PUI) exclusively in the upper cortical layers.
- This research provides new insights into the distinct contributions of glial and neuronal GJ in epilepsy.
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