Functional and morphological evidence of age-related denervation in rat laryngeal muscles

Colleen A. McMullen, Francisco H. Andrade

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Laryngeal muscle dysfunction compromises voice, swallowing, and airway protection in elderly adults. Laryngeal muscles and their motor neurons and their motor neurons communicate via the neuromuscular junction (NMJ). We tested the hypothesis that aging disrupts NMJ organization and function in the laryngeal thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles We determined NMJ density and size and acetylcholine receptor (AChR) subunit mRNAs in TA and PCA muscles from 6-, 18-, and 30- month old-rats. NMJ function was determined with tubocurarine (TC) and contractions during nerve and muscle stimulation. NMJ size, abundance, and clustering decreased in 30-month TA and PCA muscles. AChRe mTNA and protein increased with age in both muscles. AChRg mRNA increased with age in both muscles while protein content increased in TA only. Aging PCA and TA were more sensitive to TC, demonstrating functional evidence of denervation. These results demonstrate that NMJs become smaller and less abundant in aging TA and PCA muscles.

Original languageEnglish
Pages (from-to)435-442
Number of pages8
JournalJournals of Gerontology - Series A Biological Sciences and Medical Sciences
Volume64
Issue number4
DOIs
StatePublished - Apr 2009

Bibliographical note

Funding Information:
The authors thank Joey Bose and Tom Newcomb for technical assistance, and Joseph C. Stemple and Lisa B. Thomas for valuable advice and discussion. This work was supported by National Institutes of Health grant DC-007983 (to C.A.M.).

Keywords

  • Aging
  • Larynx
  • Neuromuscular junction

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology

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