Persistently decreased basal synaptic inhibition of hippocampal CA1 pyramidal neurons after neonatal hypoxia-induced seizures

Russell M. Sanchez, Jason A. Justice, Kun Zhang

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Hypoxia is the most common cause of neonatal seizures and can lead to epilepsy, but the epileptogenic mechanisms are not yet understood. We have previously shown that hypoxia-induced seizures in the neonatal rat result in acutely decreased amplitudes and frequency of spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs) in hippocampal CA1 pyramidal neurons. In the current study, we asked whether such changes persist for several days following hypoxia-induced seizures. Similar to the acute findings, we observed decreased frequency and amplitudes of sIPSCs and decreased mIPSC amplitudes in CA1 pyramidal neurons at 3-5 days after hypoxia. However, in contrast to the acute findings, we observed no differences between hypoxia-treated and control groups in mIPSC frequency. Additionally, by 7 days after hypoxia, sIPSC amplitudes in the hypoxia group had recovered to control levels, but sIPSC frequency remained decreased. These data indicate that the persistently decreased sIPSC frequency result from decreased firing of presynaptic inhibitory interneurons, with only transient possible changes in postsynaptic responses to GABA release.

Original languageEnglish (US)
Pages (from-to)159-167
Number of pages9
JournalDevelopmental Neuroscience
Volume29
Issue number1-2
DOIs
StatePublished - Dec 1 2006

Keywords

  • GABA
  • Hypoxic encephalopathy
  • Inhibitory postsynaptic currents
  • Neonatal hypoxia-induced seizures
  • Voltage clamp recordings

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience

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