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Immature Status Epilepticus : In Vitro Models Reveal Differences in Cholinergic Control and HFO Properties of Adult CA3 Interictal Discharges in Temporal vs Septal Hippocampus

Mikroulis, Apostolos LU ; Lisgaras, Christos Panagiotis and Psarropoulou, Caterina (2018) In Neuroscience 369. p.386-398
Abstract

We have earlier demonstrated that a Status Epilepticus (SE) during CNS development has long-lasting effects on cholinergic neurotransmission, detectable in vitro and in vivo. In this work, we aimed to localize changes in temporal (T) vs septal (S) hippocampus and to correlate adult CA3 interictal epileptiform discharge (IED) frequency changes to those of Ripples (R) and Fast Ripples (FR) of the High-Frequency Oscillations (HFOs). Spontaneous IEDs were induced by bathing slices in Mg2+-free ACSF or in 4-Aminopyridine (4-AP, 50 µM) and data were analyzed separately for each model. IED frequencies were similar in same origin normal (N) slices across models, but differed in SE slices, being lower in Mg2+-free ACSF than... (More)

We have earlier demonstrated that a Status Epilepticus (SE) during CNS development has long-lasting effects on cholinergic neurotransmission, detectable in vitro and in vivo. In this work, we aimed to localize changes in temporal (T) vs septal (S) hippocampus and to correlate adult CA3 interictal epileptiform discharge (IED) frequency changes to those of Ripples (R) and Fast Ripples (FR) of the High-Frequency Oscillations (HFOs). Spontaneous IEDs were induced by bathing slices in Mg2+-free ACSF or in 4-Aminopyridine (4-AP, 50 µM) and data were analyzed separately for each model. IED frequencies were similar in same origin normal (N) slices across models, but differed in SE slices, being lower in Mg2+-free ACSF than in 4-AP, suggesting a post-SE long-term increase in a K+ conductance. Rs and FRs detected within IEDs had generally higher power in 4-AP than in Mg2+-free ACSF; FR/R ratio was the highest in T-SE slices in 4-AP and similar in all other slice groups. Carbachol or eserine increased IED rates universally, but had region- and conditioning-specific effects on HFOs, suggesting that IED frequency and HFOs represent possibly independent indices of excitability. The muscarinic antagonist atropine depressed IED rates with increasing effectiveness in S slices post-SE in both models. In conclusion, the long-term effects of an immature SE are region-specific within the hippocampus, affect differently synchronizing components like the IED frequency and HFOs and may shape neurotransmitter effects (ACh) on neuronal networks, thus affecting seizure threshold and information processing, especially in behavioral conditions of rising extracellular ACh levels.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
high-frequency oscillations, interictal, muscarinic, seizures, septal hippocampus, temporal hippocampus
in
Neuroscience
volume
369
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:85037691158
ISSN
0306-4522
DOI
10.1016/j.neuroscience.2017.11.029
language
English
LU publication?
no
id
e42c35b7-1190-4c3d-8204-1be9ae20121b
date added to LUP
2017-12-20 14:53:13
date last changed
2018-01-07 12:29:28
@article{e42c35b7-1190-4c3d-8204-1be9ae20121b,
  abstract     = {<p>We have earlier demonstrated that a Status Epilepticus (SE) during CNS development has long-lasting effects on cholinergic neurotransmission, detectable in vitro and in vivo. In this work, we aimed to localize changes in temporal (T) vs septal (S) hippocampus and to correlate adult CA3 interictal epileptiform discharge (IED) frequency changes to those of Ripples (R) and Fast Ripples (FR) of the High-Frequency Oscillations (HFOs). Spontaneous IEDs were induced by bathing slices in Mg<sup>2+</sup>-free ACSF or in 4-Aminopyridine (4-AP, 50 µM) and data were analyzed separately for each model. IED frequencies were similar in same origin normal (N) slices across models, but differed in SE slices, being lower in Mg<sup>2+</sup>-free ACSF than in 4-AP, suggesting a post-SE long-term increase in a K<sup>+</sup> conductance. Rs and FRs detected within IEDs had generally higher power in 4-AP than in Mg<sup>2+</sup>-free ACSF; FR/R ratio was the highest in T-SE slices in 4-AP and similar in all other slice groups. Carbachol or eserine increased IED rates universally, but had region- and conditioning-specific effects on HFOs, suggesting that IED frequency and HFOs represent possibly independent indices of excitability. The muscarinic antagonist atropine depressed IED rates with increasing effectiveness in S slices post-SE in both models. In conclusion, the long-term effects of an immature SE are region-specific within the hippocampus, affect differently synchronizing components like the IED frequency and HFOs and may shape neurotransmitter effects (ACh) on neuronal networks, thus affecting seizure threshold and information processing, especially in behavioral conditions of rising extracellular ACh levels.</p>},
  author       = {Mikroulis, Apostolos and Lisgaras, Christos Panagiotis and Psarropoulou, Caterina},
  issn         = {0306-4522},
  keyword      = {high-frequency oscillations,interictal,muscarinic,seizures,septal hippocampus,temporal hippocampus},
  language     = {eng},
  month        = {01},
  pages        = {386--398},
  publisher    = {Elsevier},
  series       = {Neuroscience},
  title        = {Immature Status Epilepticus : In Vitro Models Reveal Differences in Cholinergic Control and HFO Properties of Adult CA3 Interictal Discharges in Temporal vs Septal Hippocampus},
  url          = {http://dx.doi.org/10.1016/j.neuroscience.2017.11.029},
  volume       = {369},
  year         = {2018},
}