Localization and regulation of aquaporins in the murine larynx

Abstract

Conclusion: Expression of aquaporins (AQPs) in the vocal folds and the parasympathetic regulation of AQPs in the laryngeal glands may be important for controlling laryngeal secretion and vocal fold hydration. These findings are thought to be an initial step towards understanding potential mechanisms of water flow through the vocal fold surface. Objectives: Lubrication of the vocal folds is important for phonation and laryngeal defense. However, the system of water transport in the laryngeal epithelium has not yet been clarified. We investigated the expression of AQP water channnels (AQP1–9) in the murine larynx and examined the neural regulating mechanisms of these subtypes. Methods: The distribution of AQPs (AQP1–9) in the murine larynx was examined by immunohistochemistry. Next, the neural mechanism regulating AQPs in the larynx was investigated using unilaterally vagotomized mice. Results: AQP1, 4, and 5 were expressed in the laryngeal epithelium including the vocal folds. Vocal fold AQP expression was minimal at the vocal process. AQP2, 3, 5, 6, 7, and 8 were localized to the submucosal glands. Expression of AQPs in the vagotomized region was significantly decreased compared with the contralateral intact side. The expression in the laryngeal glands was also decreased in the aged mice.

Keywords::

• Water channel
• vocal fold
• immunohistochemistry
• vagotomy
• vocal process
• submucosal gland
• parasympathetic nerve

Acknowledgment

This work was supported by Grant-in-Aid for Scientific Research (B) 21390463 from the Japan Society for the Promotion of Science.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.