Functional roles of the sweet taste receptor in oral and extraoral tissues

Abstract

Purpose of reviewThis review summarizes and discusses the current knowledge about the physiological roles of the sweet taste receptor in oral and extraoral tissues.Recent findingsThe expression of a functional sweet taste receptor has been reported in numerous extragustatory tissues, including the gut, pancreas, bladder, brain and, more recently, bone and adipose tissues. In the gut, this receptor has been suggested to be involved in luminal glucose sensing, the release of some satiety hormones, the expression of glucose transporters, and the maintenance of glucose homeostasis. More recently, the sweet taste receptor was proposed to regulate adipogenesis and bone biology.SummaryThe perception of sweet taste is mediated by the T1R2/T1R3 receptor, which is expressed in the oral cavity, wherein it provides input on the caloric and macronutrient contents of ingested food. This receptor recognizes all the chemically diverse compounds perceived as sweet by human beings, including natural sugars and sweeteners. Importantly, the expression of a functional sweet taste receptor has been reported in numerous extragustatory tissues, wherein it has been proposed to regulate metabolic processes. This newly recognized role of the sweet taste receptor makes this receptor a potential novel therapeutic target for the treatment of obesity and related metabolic dysfunctions, such as diabetes and hyperlipidemia.

Sweet Taste Perception is Associated with Body Mass Index at the Phenotypic and Genotypic Level

“…For example, the neurobiology of food reward might help explain why the use of non-caloric sweeteners can result in weight gain without affecting calorie intake (Heid et al, 2010). Lastly, apart from the neurological and other possible mechanisms explained above, sweet taste receptors in the mouth or guts can also control metabolism through various mechanisms, such as influencing insulin secretion (Kyriazis et al, 2014;Laffitte et al, 2014). Regardless of the scenario, sweet taste perception appears to play an important role in regulating BMI.…”

“…Sweetness is detected by sweet taste receptors in the oral cavity, which send a signal to the brain where taste sensation is elicited (Rolls, 2015). Sweet taste receptors are also expressed along the digestive system, including the pancreas, bladder, gastrointestinal, and adipose tissues (Laffitte et al, 2014), where they do not evoke sweet sensation but are involved in many physiological functions, including glucose homeostasis (Laffitte et al, 2014), insulin secretion (Kyriazis et al, 2014), and adipogenesis (Masubuchi et al, 2013).…”

Taste receptors in the gastrointestinal system

“…The cephalic phase insulin release (CPIR) after glucose ingestion or the induction of salivary, gastric, and pancreatic secretions in response to a meal are good examples of conditioned physiological responses [3]. In fact, oral ingestion of glucose generates higher insulin release than a similar amount of glucose directly injected intravenously [10,11]. The higher insulin secretion after glucose ingestion most likely results from the strengthening of CPIR with the stimulation of sweet receptors in gut enteroendocrine cells that further enhance blood insulin via incretin hormones such as glucagon-like peptide 1 (GLP-1).…”

Exploring the biological consequences of conformational changes in aspartame models containing constrained analogues of phenylalanine

“…The detection of sweet-tasting compounds (carbohydrates and non-caloric sweeteners) is mediated by a heterodimeric receptor composed of two subunits, namely T1R2 and T1R3. Moreover, this receptor modulates glucose transporters and glucose homeostasis in other ''non-taste'' organs (gastrointestinal tract, pancreas, bladder, adipose tissues, and brain) demonstrating to show a potential as new therapeutic target 2,3 . Small molecule inhibitors of sweet receptors have been demonstrated to reduce glucose absorption and calorie uptake providing an alternative strategy for the treatment of obesity and its related diseases.…”