Permanent reduction of seizure threshold in post-ischemic CA3 pyramidal neurons. - Archive ouverte HAL Access content directly
Journal Articles Journal of Neurophysiology Year : 2000

Permanent reduction of seizure threshold in post-ischemic CA3 pyramidal neurons.

(1) , (1) , (1) , (1) , (1)
1

Abstract

The effects of ischemia were examined on CA3 pyramidal neurons recorded in hippocampal slices 2-4 mo after a global forebrain insult. With intracellular recordings, CA3 post-ischemic neurons had a more depolarized resting membrane potential but no change of the input resistance, spike threshold and amplitude, fast and slow afterhyperpolarization (AHP) or ADP, and firing properties in response to depolarizing pulses. With both field and whole-cell recordings, synaptic responses were similar in control and post-ischemic neurons. Although there were no spontaneous network-driven discharges, the post-ischemic synaptic network had a smaller threshold to generate evoked and spontaneous synchronized burst discharges. Thus lower concentrations of convulsive agents (kainate, high K(+)) triggered all-or-none network-driven synaptic events in post-ischemic neurons more readily than in control ones. Also, paired-pulse protocol generates, in post-ischemics but not controls, synchronized field burst discharges when interpulse intervals ranged from 60 to 100 ms. In conclusion, 2-4 mo after the insult, the post-ischemic CA3 pyramidal cells are permanently depolarized and have a reduced threshold to generate synchronized bursts. This may explain some neuropathological and behavioral consequences of ischemia as epileptic syndromes observed several months to several years after the ischemic insult.
Embargoed file
Embargoed file
Ne sera jamais visible
Loading...

Dates and versions

inserm-00485226 , version 1 (20-05-2010)

Identifiers

  • HAL Id : inserm-00485226 , version 1
  • PUBMED : 10758114

Cite

Patrice Congar, Jean-Luc Gaïarsa, Théodora Popovici, Yezekiel Ben-Ari, Valérie Crépel. Permanent reduction of seizure threshold in post-ischemic CA3 pyramidal neurons.. Journal of Neurophysiology, 2000, 83 (4), pp.2040-6. ⟨inserm-00485226⟩

Collections

INSERM UNIV-AMU
37 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More