Keywords
smooth muscle
Abstract
Initially, tas2r receptors were believed to be only in the taste cells of the tongue, from where they sent signals to the central nervous system to avoid ingesting toxic plants. However, recent research has demonstrated expression of these in other tissues, including airway smooth muscle, arteries, detrusor, stomach cells, and endometrium.
This review investigated the expression and function of tas2r in smooth muscle through a literature search in PubMed and Scielo, following the prism prompts and using the keywords: bitter taste receptors, function and smooth muscle. 30 of 34 articles obtained that met the inclusion and exclusion criteria were analyzed.
In humans, the tas2r2, tas2r10, tas2r14 and tas2r31 subtypes are the most expressed in airway smooth muscle. Agonists of these receptors cause smooth muscle relaxation comparable to that of β-agonist bronchodilators, suggesting that they could be used in treatments for asthma and COPD. Additionally, some tas2r agonists have been shown to be more effective than current adrenergic bronchodilators in both mice and humans, thus offering better treatment options for asthma.
Tas2r are also present in the gastrointestinal system, where they modulate hormonal levels and improve the secretion of body fluids. Its participation has been observed in energy homeostasis and the secretion of hormones such as ghrelin. In the cardiovascular system, tas2r perform inotropic functions and generate relaxation of the aorta and other arteries, suggesting a role in regulating vascular tone.
In the genitourinary system, tas2r regulates inflammatory responses and detrusor muscle contractility, providing potential to treat overactive bladder. Furthermore, they appear to influence the relaxation of the myometrium, which is why they represent a target for the development of effective tocolytics in the management of premature birth.
In conclusion, tas2r are widely distributed in various tissues outside the oral cavity, and play crucial roles in physiological regulation. Tas2r agonists could hold promise for new treatments of respiratory, cardiovascular, gastrointestinal, and genitourinary diseases. However, additional studies are required to clarify its mechanisms of action and explore other potential functions.
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