Research article summary (published 22 Oct 2007):

Synaptic inputs to granule cells of the dorsal cochlear nucleus.

Full 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 microm 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, GABA(A) 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.

Author information

Author/s: Balakrishnan, Veeramuthu (V); Trussell, Laurence O (LO);

Affiliation: Oregon Hearing Research Center and Vollum Institute, L335A, 3181 S. W. Sam Jackson Park Rd., Portland, OR 97239, USA.

Grants: R37NS-028901 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)

Reference: 2008-Jan; vol 99 (issue 1) : pp 208-19

Dates: Created 2008/01/15; Completed 2008/03/24;

PMID: 17959739, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals Auditory Pathways - cytology; drug effects; physiology Auditory Perception - drug effects; physiology Cell Size Cochlear Nucleus - cytology; drug effects; physiology Excitatory Amino Acid Antagonists - pharmacology Excitatory Postsynaptic Potentials - drug effects; physiology GABA Antagonists - pharmacology Glycine - metabolism Hydrazines Inhibitory Postsynaptic Potentials - drug effects; physiology Neural Inhibition - drug effects; physiology

Neurons - cytology; drug effects; physiology Organ Culture Techniques Patch-Clamp Techniques Rats Rats, Wistar Reaction Time - drug effects; physiology Receptors, AMPA - drug effects; physiology Receptors, N-Methyl-D-Aspartate - drug effects; physiology Staining and Labeling Synapses - drug effects; physiology; ultrastructure Synaptic Transmission - drug effects; physiology gamma-Aminobutyric Acid - metabolism

Associated Chemicals: Alexa 488 hydrazide (0) ; Excitatory Amino Acid Antagonists (0) ; GABA Antagonists (0) ; Hydrazines (0) ; Receptors, AMPA (0) ; Receptors, N-Methyl-D-Aspartate (0) ; gamma-Aminobutyric Acid (56-12-2) ; Glycine (56-40-6)

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