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Evidence for stretch feedback in the thyroarytenoid muscle and potential implications in spasmodic dysphonia
Author(s) -
Reed Mitchell,
Huff Alyssa,
Iceman Kimberly,
Mian Seema,
Howland Dena,
Pitts Teresa
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.547.9
Subject(s) - muscle spindle , proprioception , anatomy , pulmonary stretch receptors , electromyography , larynx , agonist , breathing , neuroscience , muscle contraction , medicine , receptor , biology , respiratory system , afferent
Muscle position feedback, via receptors for stretch (muscle spindles) and force (golgi tendon organs), is critical for the muscular coordination and proprioception that is essential for most movements. Muscle spindles are innervated by gamma motoneurons that modulate their sensitivity to stretch. Recent reports suggest that 5‐HT 1D receptors can modulate gamma motoneurons. Adduction of the vocal folds in the larynx is regulated by the thyroarytenoid muscle, which is active during breathing, cough, swallow, and vocalization. We tested the hypothesis that activation of gamma motoneurons via 5‐HT 1D agonists would modulate stretch‐dependent thyroarytenoid activity. Muscle activity (electromyography, EMG) of both the left and right thyroarytenoid muscles was monitored in freely‐breathing sodium pentobarbital anesthetized Sprague Dawley rats. The thyroid and cricoid cartilages were mechanically stretched in an inferior‐superior direction before and after the addition of the 5‐HT 1D agonist L‐694,247. Stretching elicited EMG activity from the thyroarytenoid muscle, which increased with the addition of the agonist. Similarly, phasic EMG activity observed during breathing increased with sustained stretching, and further increased with addition of the agonist. These results provide evidence that the previously reported “spindle‐like” structures act in a stretch feedback manner, and modulation of receptors known to exist on gamma motoneurons can amplify this feedback. Identifying and understanding stretch reception in muscles of the larynx may be pivotal to determining the mechanisms of voice disorders including muscle tension dysphonia and spasmodic dysphonia. Support or Funding Information This work was supported by NIH grants HL 111215, HL 103415 and OT20D001983, the Craig F. Neilson Foundation Pilot Research Grant 546714, Veterans Affairs Rehabilitation, Research and Development RCSB92495 (DRH), Kentucky Spinal Cord and Head Injury Research Trust, Rebecca F. Hammond Endowment (DRH), and the Commonwealth of Kentucky Challenge for Excellence. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .