Synaptic inputs to granule cells of the dorsal cochlear nucleus

Veeramuthu Balakrishnan, Laurence Trussell

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The mammalian dorsal cochlear nucleus (DCN) integrates auditory nerve input with nonauditory signals via a cerebellar-like granule cell circuit. Although granule cells carry nonauditory information to the DCN, almost nothing is known about their physiology. Here we describe electrophysiological features of synaptic inputs to granule cells in the DCN by in vitro patch-clamp recordings from P12 to P22 rats. Granule cells ranged from 6 to 8 μm in cell body diameter and had high-input resistance. Excitatory postsynaptic currents consisted of both AMPA receptor-mediated and N-methyl-D-aspartate receptor-mediated currents. Synaptically evoked excitatory postsynaptic currents ranged from -25 to -140 pA with fast decay time constants. Synaptic stimulation evoked both short- and long-latency synaptic responses that summated to spike threshold, indicating the presence of a polysynaptic excitatory pathway in the granule cell circuit. Synaptically evoked inhibitory postsynaptic currents in Cl--loaded cells ranged from -30 to -1,021 pA and were mediated by glycine and, to a lesser extent, GABAA receptors. Unlike cerebellar granule cells, DCN granule cells lacked tonic inhibition by GABA. The glycinergic synaptic conductance was mediated by heteromeric glycine receptors and was far stronger than the glutamatergic conductance, suggesting that glycinergic neurons may act to gate nonauditory signals in the DCN.

Original languageEnglish (US)
Pages (from-to)208-219
Number of pages12
JournalJournal of Neurophysiology
Volume99
Issue number1
DOIs
StatePublished - Jan 2008

Fingerprint

Cochlear Nucleus
Excitatory Postsynaptic Potentials
Glycine Receptors
Cochlear Nerve
Inhibitory Postsynaptic Potentials
AMPA Receptors
GABA-A Receptors
N-Methyl-D-Aspartate Receptors
Glycine
gamma-Aminobutyric Acid
Reaction Time
Neurons

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Synaptic inputs to granule cells of the dorsal cochlear nucleus. / Balakrishnan, Veeramuthu; Trussell, Laurence.

In: Journal of Neurophysiology, Vol. 99, No. 1, 01.2008, p. 208-219.

Research output: Contribution to journalArticle

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