Development of acetylcholine receptors in cultured outer hair cells

David Z.Z. He*, Jing Zheng, Peter Dallos

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Efferents, originating in the superior olivary complex, preferentially synapse with cochlear outer hair cells (OHCs), with acetylcholine (ACh) as their primary neurotransmitter. The OHC ACh receptors (AChRs), which have unusual pharmacology, have been cloned and identified as a new subunit (α9) of the nicotinic AChR family. The expression of α9 AChRs is first detected before birth and peaks between 6 and 10 days after birth (DAB) in developing mice and rats, while functional maturation of the receptor, as determined by measuring the ACh-induced currents, takes place between 6 and 12 DAB. In this study we attempted to examine the development of AChRs in OHCs grown in explanted cultures, deprived of efferent innervation. ACh-induced currents were used as an assay. Reverse transcription-PCR analysis was also performed to detect the expression of α9 subunit from cultured OHCs. PCR study indicates that mRNA of the α9 subunit was expressed in primary cochlear cultures, similar to that seen in the cochleae of developing animals. Measurement of whole-cell currents showed that ACh-induced outward current was first detected around 5 days in a fraction of cultured OHCs. The number of responsive cells increased between 5 and 12 days in culture. The size of ACh-induced currents also increased during this period. These results suggest that the development of AChRs in cultured OHCs is not affected by removal of efferent innervation.

Original languageEnglish (US)
Pages (from-to)113-125
Number of pages13
JournalHearing research
Volume162
Issue number1-2
DOIs
StatePublished - 2001

Funding

This work has been supported by a grant from the Deafness Research Foundation and by NIH Grants R01 DC 04696 to D.H., R01 DC 00708 to P.D. from the National Institute of Deafness and Other Communication Disorders. We thank Mr. Kevin Long for some technical assistance.

Keywords

  • α9 acetylcholine receptor
  • Cochlea
  • Development
  • Efferent innervation
  • Gerbil
  • Neural regulation
  • Outer hair cell
  • PCR
  • Potassium channel
  • Tissue culture
  • Voltage-clamp

ASJC Scopus subject areas

  • Sensory Systems

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