The parasympathetic salivatory nuclei are located in the medulla oblongata, which are under descending control from higher centers of the brain, such as the cerebral cortex, hypothalamus and limbic system. Therefore, the suppression of salivary flow under stress conditions is due to inhibition in the salivatory nuclei. In addition to this mechanistic effect, the results of experimental studies suggest the existence of an inhibitory effect of the sympathetic nervous system on parasympathetic-stimulated salivary secretion from the salivary gland. In this paper, the suppressive mechanism of salivary secretion is discussed.

Mechanical plaque control using a toothbrush is sometimes very difficult in elderly individuals who require long-term care. Chemical control using a safe and effective mouthwash is expected to be useful in the treatment and prevention of oral infection. To clarify its utility in oral infection, we investigated antioxidant activity to eliminate reactive oxygen species (ROS) and antimicrobial activity against oral microbes of ethanol-free Listerine^® Natural Care (Listerine NC) mouthwash. The antioxidant effects on the direct scavenging ability of ROS such as the hydroxyl radical (HO^･) and superoxide (O₂^･‒) were measured using an electron spin resonance (ESR) method. The antimicrobial activity is evaluated using the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of five species of oral microbes including Candida albicans, Streptococcus mutans, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia. Listerine NC showed high scavenging activity against HO^･ without showing any O₂^･‒scavenging activity. Listerine NC also possessed strong antibacterial and bactericidal activity against all oral bacteria measured in the experiment even at a concentration of 25％ or less. These results suggest that Listerine NC may act as an anti-inflammatory agent in oral infections through its direct antioxidant action and effective antibacterial activity against oral microorganisms, suggesting its usefulness in oral infections.

BACKGROUND：Non-steroidal anti-inflammatory drugs (NSAIDs) have been widely used for the management of pain and inflammation. However, little remains known about the effects of NSAIDs on synovitis of the human temporomandibular joint (TMJ).

Cyclooxygenase (COX) inhibitor are one of main NSAIDs. This study investigate the effects of COX inhibitor on fibroblast-like synoviocytes (FLS) derived from the human TMJ.

METHODS：Human synovial tissue was obtained from a patient with internal derangement who underwent arthroscopy of the TMJ. FLSs were prepared from the tissues using the outgrowth method. A COX inhibitor (indometacin or celecoxib) was added to the IL-1β stimulating cells in culture. Gene expression profiling was performed using microarray analysis.

RESULTS：The expressions of IL-23A, IL-11, and IL-33, which were up-regulated in FLSs stimulated by IL-1xxxwere down-regulated in the cells treated by COX inhibitors.

CONCLUSION：COX inhibitors such as indomethacin and celecoxib reduce the gene expression of inflammatory cytokines induced by IL-1β Our results suggest that these COX inhibitors are useful for treating synovitis in TMJ.