IADR Abstract Archives
Physiological Function of the Murine Bitter Taste Receptor Tas2r108
Objectives: It has recently been reported that type 2 taste receptors (T2Rs) are expressed in various cranio-facial tissues such as gingiva and salivary glands. Human T2R38, found in gingiva, is associated with gingival innate immunity and change in the risk of dental caries. It suggests that T2Rs may play important physiological roles besides bitter taste reception. However, functions of T2Rs in extra-oral tissue remain poorly understood. We firstly studied the expression level of T2Rs in murine exocrine glands using real-time PCR. Murine t2r108, among 35 T2Rs, was the most highly expressed in every observed exocrine gland as well as in tongue papillae. It would be important to reveal the exact location and/or the specific agonist of t2r108.
Methods: In situ hybridization (ISH) was performed to determine expression site of tas2r108 mRNA in the salivary glands and to provide a clue to find its physiological function. Messenger RNAs were extracted from the submandibular gland for generating digoxigenin labeled-cRNA probes. These probes were transcribed in anti-sense and sense orientation using T7 RNA polymerase.
To determine whether tas2r108 expressed in salivary glands respond to bitter taste compounds, tas2r108 specific agonist should be identified. We performed to calcium imaging using tas2r108 transfected chinese hamster ovary (CHO) cells.
Results: ISH results showed that tas2r108 was expressed in acinar and ductal cells. Interestingly, expression levels of tas2r108 in the salivary glands were higher in acinar cells than in ductal cells. Before performing calcium imaging, we performed PCR to determine that tas2r108 was transfected into CHO cells and found that tas2r108 was expressed in these cells.
Conclusions: Although the exact physiological role has not yet clarified, we suggest that tas2r108 expressed in the salivary glands may influence in both saliva secretion and modification of saliva composition, however, its contribution is more on saliva secretion. The Tas2r108 may function protecting the organism agianst probale toxic substances by eliciting secretion of saliva. The physiological function of Tas2r108 would be clarified by studyingtas2r108 knock-out mice.
Methods: In situ hybridization (ISH) was performed to determine expression site of tas2r108 mRNA in the salivary glands and to provide a clue to find its physiological function. Messenger RNAs were extracted from the submandibular gland for generating digoxigenin labeled-cRNA probes. These probes were transcribed in anti-sense and sense orientation using T7 RNA polymerase.
To determine whether tas2r108 expressed in salivary glands respond to bitter taste compounds, tas2r108 specific agonist should be identified. We performed to calcium imaging using tas2r108 transfected chinese hamster ovary (CHO) cells.
Results: ISH results showed that tas2r108 was expressed in acinar and ductal cells. Interestingly, expression levels of tas2r108 in the salivary glands were higher in acinar cells than in ductal cells. Before performing calcium imaging, we performed PCR to determine that tas2r108 was transfected into CHO cells and found that tas2r108 was expressed in these cells.
Conclusions: Although the exact physiological role has not yet clarified, we suggest that tas2r108 expressed in the salivary glands may influence in both saliva secretion and modification of saliva composition, however, its contribution is more on saliva secretion. The Tas2r108 may function protecting the organism agianst probale toxic substances by eliciting secretion of saliva. The physiological function of Tas2r108 would be clarified by studyingtas2r108 knock-out mice.