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.
|Number of pages||8|
|Journal||Journals of Gerontology - Series A Biological Sciences and Medical Sciences|
|State||Published - Apr 2009|
Bibliographical noteFunding 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.).
- Neuromuscular junction
ASJC Scopus subject areas
- Geriatrics and Gerontology