Endoplasmic reticulum stress affects mouse salivary protein secretion induced by chronic administration of an α1-adrenergic agonist.

Stress stimulates both the sympathetic-adrenomedullary and hypothalamus-pituitary-adrenal axes. Activation of these axes results in the release of catecholamines, which in turn affects salivary secretion. Thus, repetitive stimulation of the α1-adrenergic receptor could be useful for studying the effects of chronic stress on the salivary gland. Salivary protein concentration and kallikrein activity were significantly lower in mice following chronic phenylephrine (PHE) administration. Chronic PHE administration led to significantly increased expression of the 78-kDa glucose-regulated protein, activating transcription factor 4, and activating transcription factor 6. Histological analyses revealed a decrease in the size of the serous cell and apical cytoplasm. These results suggest that repetitive pharmacological stimulation of the sympathetic nervous system elicits ER stress and translational suppression. In addition, PHE-treated mice exhibited a decrease in intracellular Ca2+ influx elicited by carbachol, a muscarine receptor agonist in the submandibular gland. The present findings suggest that chronic psychological, social, and physical stress could adversely affect Ca2+ regulation.

The Candida species that are important for the development of atrophic glossitis in xerostomia patients.

BACKGROUND: The purpose of this study was to clarify the species of Candida that are important for the development of atrophic glossitis in xerostomia patients. METHODS: A total of 231 patients with subjective dry mouth were enrolled in the present study. Logistic regression analysis was performed to clarify the contribution of each Candida species and other variables to the development of atrophic glossitis. The dependent variable was the absence/presence of atrophic glossitis. The Candida colony-forming units (CFU) of C. albicans, C. glabrata, C. tropicalis, and C. krusei, as well as age, gender, resting (RSFR) and stimulated (SSFR) whole salivary flow rate, and denture-wearing status, were treated as explanatory variables. RESULTS: Logistic regression analysis showed that two factors were closely associated with the presence of atrophic glossitis: an increase in C. albicans CFU and a decrease in the SSFR. CONCLUSIONS: C. albicans, but not non-albicans Candida, was associated with atrophic glossitis in xerostomia patients who had no systemic predisposing factors, indicating that C. albicans remains a treatment target for Candida-related atrophic glossitis.

Inhibition of pilocarpine-induced saliva secretion by adrenergic agonists in ICR mice.

The aim of the present study was to clarify the effects of the adrenoceptor agonist isoproterenol (IPR) on saliva secretion stimulated by the muscarinic receptor agonist pilocarpine (PILO) in mice. Mice were injected with either 0.5 mg/kg, i.p. PILO alone or simultaneously with 2 mg/kg, i.p., IPR to evaluate the inhibitory effects of adrenoceptor agonists on saliva secretion. The mechanisms underlying changes in saliva flow rate were evaluated by histological examination of aquaporin 5 (AQP5) and saliva flow rate using the adenylate cyclase (AC) inhibitor SQ22536 (0.25 mg per mouse, s.c.), which was administered 30 min prior to PILO and/or IPR. Saliva volume decreased significantly in the mice treated simultaneously with PILO + IPR compared with that in mice treated with PILO alone. Changes in the intracellular localization of AQP5 were seen in PILO + IPR-treated mice, and those changes were reversed by SQ22536 pretreatment. In addition, the decreased salivary flow rate in the PILO + IPR-treated mice was partially restored by SQ22536 pretreatment. There were no significant changes in intracellular calcium or ATP levels among the groups. The results of the present study suggest the existence of an inhibitory effect of the sympathetic nervous system on parasympathetic-stimulated salivary secretion from the salivary gland.

The Relationship between Habitual Dietary Intake and Gut Microbiota in Young Japanese Women.

Recent studies have shown that dietary content affects the health of the host by changing the gut microbiota. However, little is known about the association of microbiota composition with habitual diet in Japanese people. Here, we aimed to clarify the relationship between the fecal microbiota and habitual dietary intake of micronutrients, macronutrients and food groups in healthy young Japanese women. Analysis of fecal microbiota was performed by the terminal restriction fragment length polymorphism (T-RFLP) method, and a dietary survey was conducted over three consecutive days using a weighed food record method. T-RFLP pattern analysis divided the subjects into two clusters, where cluster A group had a high relative abundance of Bacteroides and Clostridium cluster IV, and cluster B group had a high relative abundance of Bifidobacterium and Lactobacillales. Cluster A group also had lower intakes of iron and vitamin K and higher intakes of mushrooms and snacks than cluster B group. Analysis of Spearman rank correlations found several significant relationships between fecal microbiota and intake of nutrients and food groups. Bifidobacterium was correlated with iron intake, and Clostridium cluster XI was negatively correlated with intakes of cholesterol and eggs. These results suggest that dietary habits may strongly affect Bifidobacterium, Bacteroides and Clostridium abundance in the gut microbiota of young Japanese women. This is the first study to show relationships between fecal microbiota and habitual dietary intake in Japanese people. Accumulation of results from similar studies will help to elucidate the relationships between dietary intake and diseases in Japanese people.

Salivary 8-OHdG Induction by Physical Exercise Training Under Food Restriction.

OBJECTIVE: We previously reported that physical exercise under food restriction induced alterations in saliva secretion, including a decrease in salivary kallikrein activity, while exercise training alone did not affect the overall saliva content. The objective of the present study was to examine the involvement of oxidative stress in alterations of salivary secretion due to physical exercise under food restriction. METHODS: Male ICR mice at 32 weeks of age weighing from 39 to 50 g were divided into three groups: an exercise group with food restriction (EXP), an exercise group without food restriction (EXA) and a control group (CTL). The EXP group was fed the same amount of diet as the CTL group (pair-feeding). The EXP and EXA groups had access to a "voluntary running wheel" for exercise. The pilocarpine-stimulated whole saliva was collected from the oral cavity by micro-pipette over 15 min for 12 weeks after the beginning of the experiment. The salivary and serum 8-Hydroxy-2'-deoxyguanosine (8-OHdG) were determined. RESULTS: The salivary 8-OHdG levels in the EXP group were significantly higher than in the CTL and EXA groups (p<0.01). CONCLUSION: The alterations of salivary secretion in mice undergoing chronic exercise training under a food-restricted diet may occur as a result of oxidative stress.

Availability of saliva for the assessment of alterations in the autonomic nervous system caused by physical exercise training.

OBJECTIVE: The purpose of the study was to assess the alterations of the autonomic nervous system activities caused by physical exercise training under food restriction using a running wheel in mice based on an analysis of saliva. METHODS: Male ICR mice, weighing 39-50 g, at 32 weeks of age were divided into three groups; an exercise with food restriction (EXP), an exercise without food restriction (EXA) and a control (CTL). The EXP group was fed the same amount of diet as the CTL group (pair-feeding). The EXP and EXA groups used a "voluntary running wheel" for exercise. The pilocarpine stimulated whole saliva was collected from the oral cavity by micropipette over 15 min 4, 8 and 12 weeks after the beginning of the experiment. The salivary flow rate, protein concentration and amylase and kallikrein activities were determined, since amylase and kallikrein release have been shown to be evoked by beta- and alpha-adrenergic receptor stimulation, respectively. RESULTS: There was no significant difference in the sera corticosterone levels among the three experimental groups. The flow rate of saliva per total salivary gland weight in the EXP was significantly lower than that in the CTL and the EXA groups. The total protein secretion and kallikrein activity decreased by 20-30% in the EXP mice between 4 and 12 weeks after the starting of experiments in comparison to the CTL mice, thus suggesting that signal transduction in the alpha-sympathetic nervous system was downregulated. There was no significant difference in the amylase activity between the EXP and the CTL groups. CONCLUSION: Physical exercise under diet control induced alterations in saliva secretion, while exercise training alone did not affect the content of saliva. The results demonstrate the availability of saliva and suggest that the present experimental situation is a suitable experimental model for sports activity performed under diet control.