Neuromuscular Junction Changes in Aged Rat Thyroarytenoid Muscle

• Published in: Annals of otology, rhinology & laryngology Vol. 111; no. 7; pp. 579 - 586
• Main Authors: Connor, Nadine P., Suzuki, Tatsutoshi, Sewall, Gregory K., Lee, Kyungah, Heisey, Dennis M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.07.2002; Annals Publishing Compagny; SAGE PUBLICATIONS, INC
• Subjects: Age Factors; Aging - physiology; Animals; Atrophy - pathology; Axons - pathology; Biological and medical sciences; Deglutition Disorders - etiology; Development. Metamorphosis. Moult. Ageing; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; Laryngeal Muscles - innervation; Laryngeal Muscles - pathology; Laryngeal Muscles - physiopathology; Medical sciences; Neural Conduction - physiology; Neuromuscular Junction Diseases - complications; Neuromuscular Junction Diseases - pathology; Neuromuscular Junction Diseases - physiopathology; Rats; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the urinary system; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Voice Disorders - etiology; aging; thyroarytenoid muscle; confocal microscopy; neuromuscular junction; Modification; Rat; Ageing; Rodentia; Exploration; Swallowing; Experimental study; Neuromuscular junction; Vertebrata; Mammalia; Animal; Quality; Physiology; Voice
• ISSN: 0003-4894; 1943-572X
• DOI: 10.1177/000348940211100703

Dynamic remodeling of neuromuscular junction (NMJ) structure is postulated as a cause of age-related muscular atrophy. Direct study of NMJ morphology in laryngeal muscles is important to our understanding of age-related decrements in voice and swallowing. The morphology of NMJs was studied in a rat model to compare young and old specimens of thyroarytenoid muscle — a muscle critical to airway protection and phonation. Fluorescent, triple-label immunohistochemical analysis and confocal microscopic visualization were used to analyze the structure of NMJs. We found that laryngeal NMJs underwent significant changes that were similar to those observed after denervation. Specifically, the axon terminal area was significantly reduced, there were a number of postsynaptic acetylcholine receptor areas unoccupied by nerve terminals, and there was increased variability in end plate architecture in the old muscles. The results of this study increase our understanding of the age-related morphological changes in the larynx, and may serve as a baseline to test the effectiveness of future interventions.