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Updated: Aug 20, 2025
In Vivo Evaluation of the Mechanical and Viscoelastic Properties of the Rat Tongue
Published on: July 6, 2017
Optogenetic activation of the tongue in spontaneously breathing mice
Michele L Singer1, Ethan S Benevides1, Sabhya Rana2
1Rehabilitation Science PhD Program, University of Florida, 32611, the United States of America; Department of Physical Therapy, University of Florida, 32611, the United States of America; Breathing Research and Therapeutics Center, University of Florida, 32610, the United States of America; McKnight Brain Institute, 32610, University of Florida, the United States of America.
Abstract:
Inadequate tongue muscle activation contributes to dysarthria, dysphagia, and obstructive sleep apnea. Thus, treatments which increase tongue muscle activity have potential clinical benefit. We hypothesized that lingual injection of an adeno-associated virus (AAV) encoding channelrhodopsin-2 (ChR2) would enable light-induced activation of tongue motor units during spontaneous breathing. An AAV serotype 9 vector (pACAGW-ChR2-Venus-AAV9, 8.29 × 1011 vg) was injected to the posterior tongue in adult C57BL/6J mice. After 12 weeks, mice were anesthetized and posterior tongue electromyographic (EMG) activity was recorded during spontaneous breathing; a light source was positioned near the injection site. Light-evoked EMG responses increased with the intensity and duration of pulses. Stimulus trains (250 ms) evoked EMG bursts that were comparable to endogenous (inspiratory) tongue muscle activation. Histology confirmed lingual myofiber transgene expression. We conclude that intralingual AAV9-ChR2 delivery enables light evoked lingual EMG activity. These proof-of-concept studies lay the groundwork for clinical application of this novel approach to lingual therapeutics.
