1. Neuroscience
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Sound exposure dynamically induces dopamine synthesis in cholinergic LOC efferents for feedback to auditory nerve fibers

  1. Jingjing Sherry Wu
  2. Eunyoung Yi
  3. Marco Manca
  4. Hamad Javaid
  5. Amanda M Lauer
  6. Elisabeth Glowatzki  Is a corresponding author
  1. Johns Hopkins University School of Medicine, United States
  2. Mokpo National University, Republic of Korea
Research Article
  • Cited 11
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Cite this article as: eLife 2020;9:e52419 doi: 10.7554/eLife.52419

Abstract

Lateral olivocochlear (LOC) efferent neurons modulate auditory nerve fiber (ANF) activity using a large repertoire of neurotransmitters, including dopamine (DA) and acetylcholine (ACh). Little is known about how individual neurotransmitter systems are differentially utilized in response to the ever-changing acoustic environment. Here we present quantitative evidence in rodents that the dopaminergic LOC input to ANFs is dynamically regulated according to the animal's recent acoustic experience. Sound exposure upregulates tyrosine hydroxylase, an enzyme responsible for dopamine synthesis, in cholinergic LOC intrinsic neurons, suggesting that individual LOC neurons might at times co-release ACh and DA. We further demonstrate that dopamine down-regulates ANF firing rates by reducing both the hair cell release rate and the size of synaptic events. Collectively, our results suggest that LOC intrinsic neurons can undergo on-demand neurotransmitter re-specification to re-calibrate ANF activity, adjust the gain at hair cell/ANF synapses, and possibly to protect these synapses from noise damage.

Article and author information

Author details

  1. Jingjing Sherry Wu

    Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Eunyoung Yi

    College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan-gun, Republic of Korea
    Competing interests
    The authors declare that no competing interests exist.
  3. Marco Manca

    Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Hamad Javaid

    Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Amanda M Lauer

    Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4184-7374
  6. Elisabeth Glowatzki

    Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, United States
    For correspondence
    eglowat1@jhmi.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3135-658X

Funding

National Institute on Deafness and Other Communication Disorders (R01DC006476)

  • Elisabeth Glowatzki

National Institute on Deafness and Other Communication Disorders (R01DC012957)

  • Elisabeth Glowatzki

National Institute on Deafness and Other Communication Disorders (R01DC017620)

  • Amanda M Lauer

National Institute on Deafness and Other Communication Disorders (R01DC016641)

  • Amanda M Lauer

David M. Rubenstein Fund for Hearing Research

  • Amanda M Lauer

Capita Foundation

  • Amanda M Lauer

Korea Health Industry Development Institute (Korea Health Technology R&D Project HI17C0952)

  • Eunyoung Yi

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All procedures concerning animals were performed in accordance with animal protocols approved by the Johns Hopkins University Animal Care and Use Committee (IACUC). The Johns Hopkins University Office of Laboratory Animal Welfare (OLAW) Assurance number is A-3272-01.

Reviewing Editor

  1. Catherine Emily Carr, University of Maryland, United States

Publication history

  1. Received: October 3, 2019
  2. Accepted: January 23, 2020
  3. Accepted Manuscript published: January 24, 2020 (version 1)
  4. Version of Record published: February 26, 2020 (version 2)

Copyright

© 2020, Wu et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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Further reading

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