Effects of long-acting beta adrenergic agonists on vocal fold ion transport.
OBJECTIVE
Inhaled medications prescribed for the hypersensitive airway typically combine corticosteroids and long-acting beta2 adrenergic agonists (LABAs). The phonatory side effects of these combination treatments are widely recognized. However, there is limited understanding of the physiological changes induced by these medications that underlie the phonatory side effects. The objective of this study was to investigate the distinct effects of corticosteroids and LABAs on vocal fold mucosal physiology. Understanding the physiological changes to the vocal folds after corticosteroid and LABA treatments is necessary to prevent the prevalent vocal decrement associated with these medications.


METHODS
Experimental in vitro design with treatment and control groups.


METHODS
Native porcine vocal fold mucosae (N = 38) were exposed to corticosteroid or LABA treatments. Ion transport was measured continuously at baseline and after treatment. To quantify the nature of ion transport, vocal folds were also treated with chloride and sodium channel inhibitors.


RESULTS
Corticosteroid treatment did not alter ion transport. Conversely, exposure to LABAs significantly increased ion transport. This increase in ion transport was transient, observed immediately after treatment in all tissue and associated with increased chloride secretion.


CONCLUSIONS
The distinct effects of corticosteroids and LABAs on vocal fold physiology have not been examined to date. This study demonstrates that short-term treatment with LABAs, but not corticosteroids, significantly increases ion transport. These findings suggest that one underlying physiological mechanism for phonatory changes associated with inhaled treatments may be related to acute alterations in vocal fold ion transport and surface hydration.
Sivasankar
Mahalakshmi
M
Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907, USA. msivasankar@purdue.edu
Blazer-Yost
Bonnie
B
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage*; D000818:Animals; D003692:Delayed-Action Preparations; D004195:Disease Models, Animal; D005938:Glucocorticoids / Q000008:administration & dosage; D017136:Ion Transport / Q000187:drug effects*; D007818:Laryngeal Diseases / Q000188:drug therapy / Q000378:metabolism; D018408:Patch-Clamp Techniques; D013552:Swine; D014827:Vocal Cords / Q000187:drug effects / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D003692:Delayed-Action Preparations; D005938:Glucocorticoids