• International Journal of Oral Biology
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• v.43 no.1
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• pp.5-11
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• 2018

Recent findings indicate that Type 2 taste receptors (T2Rs) are expressed outside the gustatory system, including in the gastrointestinal tracts and the exocrine glands, such as the submandibular (SM), parotid (P), lacrimal (L) glands and pancreas (PC). Specifically, T2Rs are found in some of the gastrointestinal endocrine cells, and these cells secreted peptide hormones in response to stimulation by bitter-tasting compounds. The results show that T2Rs may have significant physiological roles besides bitter taste reception. The functions of the T2Rs in the exocrine glands remain poorly understood. An expression levels analysis of T2Rs will help to determine those functions in the exocrine glands. The expression levels of the T2Rs in the exocrine glands were discovered via the qPCR. C57BL/6J mice of 42~60-day-old were used. Messenger RNAs were extracted from S, P, L and PC. Cloned DNAs were synthesized by reverse transcription. Quantitative PCRs were performed using the SYBR Green method. The expression levels of the T2Rs were calculated as relative expression levels to that of the GAPDH. The statistical significance among the observed exocrine glands was tested using the variance analysis (ANOVA test). Tas2r108, out of murine 35 T2Rs, was the most highly expressed in every observed exocrine gland. This finding was similar to previous results from tongue papillae, but the expression levels were lower than those of the tongue papillae. Tas2r137 of SM, P, L and PC were expressed a little lower than that of tongue papillae. The T2Rs in the exocrine glands may play slightly different roles from those in the tongue. We suggest that physiological studies such as a patch clamp and functional $Ca^{2+}$ imaging of acinar cells are necessary for understanding the Tas2r108 functions.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.291-298
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• 2013

On this study, we treated rats with restraint stress, and observed the changes with an optical microscope. Within the salivary gland tissue, we measured cell apoptosis cycle evaluation which show positive reaction on TUNEL assay, and compared within the groups. For this study, 18 rats were divided into 3 groups; 1) 2 rats of group I were selected as a normal control. 2) 2 rats of group II, as a experimental control were placed in the restraint cone for 2 hours 3) 14 rats of group III were placed in the restraint cone for 2 hours once a day. The rats were sacrificed immediately (group II, as a experimental control), 1, 2, 3, 4, 5, 6 and 7days after application of the stress and the both parotid glands were excised. The conclusions follow. 1. 5 days after giving an confining stress to the parotid gland of Rats, we can observe the hypotropy and pus and inflammation of Rat parotid gland acinar cells, and after 7 days, we can see a cell apoptosis. 2. Through the In situ DNA end labeling assay and TUNEL dye, on serous glands, benign tumor cell increased with statistically significant result after 5 days from confining stress. And the index shows maximum value on 7th days, which is same result with histological opinion. Therefore, our study shows that a cell apoptosis can be induced by restraint stress on salivary gland tissue, and we think more study should be accomplished about the cell signaling pathway in the future.