Recent studies have demonstrated that bitter taste receptors are distributed not only in oral cavity but also in non-gustatory systems,such as the respiratory,digestive,reproductive and cardiovascular systems.The physiological role of bitter taste receptors is to recognize bitter substances or bacterial secretions,to trigger the immune response and to maintain the internal environmental homeosta-sis.In addition,oral bitter taste receptors are expressed not only in taste buds,perceiving bitter taste,but also in many other parts of periodontal tissues,which is the potential treatment target for oral infectious diseases.This review summarized the expression and distri-bution of oral bitter taste receptors which was off the taste buds and their roles in regulating oral inflammation and oral bacteria,dis-cussed the effects of genetic polymorphism of bitter taste receptor 38 subtype(TAS2R38)on innate immunity and its relationship with the susceptibility of dental caries and periodontal,aimed to provide novel ideas for the better prevention and treatment of dental caries and periodontal diseases.

OBJECTIVE To investigate the effect of arctiin （ARC）relieving lipopolysaccharide （LPS）induced inflammatory injury of human nasopharyngeal epithelial cells NP- 69. METHODS The effects of 24 h treatment of 0.000 1，0.001，0.01，0.1， 1.0，10 μmol/L ARC on the proliferation of NP-69 were determined by MTS method. After 0.01，0.1，and 1.0 μmol/L ARC was applied to NP- 69 for 24 h and NP- 69 was pre-treated with 0.01，0.1 and 1.0 μmol/L ARC for 24 h，and then stimulated with 1.0 μg/mL LPS for 24 h，scratch tests were used to detect cell migration in both experiments. LPS stimulated NP- 69 to establish an inflammation injury model. The levels of nitric oxide （NO），tumor necrosis factor α（TNF-α）interleukin-6（IL-6），and IL- 1β in cell supernatants were detected ，and mRNA and protein expression of zonula oecludens protein 1（ZO-1），β-defensin 3（BD3）， Janus kinase 1 （JAK1），signal transducer and activator of transcription 3 （STAT3） in cell supernatant were also detected. RESULTS Compared with normal group ，0.000 1，0.001，0.01，0.1，1.0，10 μmol/L ARC had no effect on the proliferation of NP-69 after 24 h treatment （P＞0.05）. ARC （0.1，1.0 μmol/L）could significantly promote the rate of cell migration （P＜0.05）. For the inflammatory injure of NP- 69 cells stimulated by LPS ，ARC（1.0 μmol/L）could significantly reduce the release of NO ， TNF-α and IL-6（P＜0.05），significantly increased mRNA and protein expression of ZO- 1 and BD 3 but decreased mRNA and protein expression of STAT 3（P＜0.01 or P＜0.05）. CONCLUSIONS ARC has the effect of reducing the inflammatory injury of NP-69 cells induced by LPS ，promoting the physical and immune defense ability of the nasal mucosa epithelial barrierunder inflammatory environment. The mechanism of action may be related to inhibiting IL- 6/JAK1/STAT3 signaling pathway.