Differences in Glycinergic mIPSCs in the Auditory Brain Stem of Normal and Congenitally Deaf Neonatal Mice

Richardson N. Leao, Sharon Oieskevich, Hong Sun, Melissa Bautista, Robert E.W. Fyffe, Bruce Walmsley

Research output: Contribution to journalArticlepeer-review

Abstract

We have investigated the fundamental properties of central auditory glycinergic synapses in early postnatal development in normal and congenitally deaf (dn/dn) mice. Glycinergic miniature inhibitory postsynaptic currents (mIPSCs) were recorded using patch-clamp methods in neurons from a brain slice preparation of the medial nucleus of the trapezoid body (MNTB), at 12-14 days postnatal age. Our results show a number of significant differences between normal and deaf mice. The frequency of mIPSCs is greater (50%) in deaf versus normal mice. Mean mIPSC amplitude is smaller in deaf mice than in normal mice (mean mIPSC amplitude: deaf, 64 pA; normal, 106 pA). Peak-scaled fluctuation analysis of mIPSCs showed that mean single channel conductance is greater in the deaf mice (deaf, 64 pS; normal, 45 pS). The mean decay time course of mIPSCs is slower in MNTB neurons from deaf mice (mean half-width: deaf, 2.9 ms; normal, 2.3 ms). Light- and electron-microscopic immunolabeling results showed that MNTB neurons from deaf mice have more (30%) inhibitory synaptic sites (postsynaptic gephyrin clusters) than MNTB neurons in normal mice. Our results demonstrate substantial differences in glycinergic transmission in normal and congenitally deaf mice, supporting a role for activity during development in regulating both synaptic structure (connectivity) and the fundamental (quantal) properties of mIPSCs at central glycinergic synapses.

Original languageEnglish
Pages (from-to)1006-1012
Number of pages7
JournalJournal of Neurophysiology
Volume91
Issue number2
DOIs
StatePublished - Feb 2004

ASJC Scopus Subject Areas

  • General Neuroscience
  • Physiology

Keywords

  • Comparative Study
  • Research Support, US. Gov't, P.H.S
  • Animals
  • Animals, Newborn
  • Brain Stem / physiology*
  • Brain Stem / ultrastructure
  • Deafness / congenital*
  • Deafness / physiopathology*
  • Glycine / physiology*
  • Immunohistochemistry
  • In Vitro Techniques
  • Mice
  • Mice, Inbred CBA
  • Microscopy, Immunoelectron
  • Neural Inhibition / physiology*
  • Synapses / physiology
  • Synapses / ultrastructure
  • Synaptic Transmission / physiology*
  • Glycine

Disciplines

  • Medical Cell Biology
  • Medical Neurobiology
  • Medical Physiology
  • Neurosciences
  • Physiological Processes

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