Effects of the antihypertensive drug captopril on human salivary secretion rate and composition

The effects of the antihypertensive drug captopril on salivary secretion rate and composition was evaluated in 24 healthy adults (18–46 yr) according to a double-blind, cross-over design. Unstimulated and paraffin-chewing stimulated whole saliva and 3% citric acid stimulated parotid and submandibtilar-sublingual (SM-SL) secretion were collected at 10.30 a.m. (about 2h after intake of breakfast) on day 0 (baseline values), day 1 (experimental acute values) and day 7 (experimental chronic values) in each treatment period. In 8 of the subjects, also morning samples were collected at 7.30 a.m., with the test subjects in a fasting condition. Whole saliva was assessed for flow rate and for concentrations of sodium, potassium, chloride, calcium and phosphate. In addition, parotid and SM-SL secretion were assessed for concentrations of total protein, hexosamine. sialic acid, lactoferrin and salivary IgA and for activities of amylase. lysozyme and salivary peroxidase. During treatment with the angiotensin converting enzyme inhibitor captopril, the secretion rates tended to increase for unstimulated and paraffin-chewing stimulated whole saliva and for parotid secretion. For salivary composition, no alterations were observed in any of the collected secretions.     

Effects of furosemide and bendroflumethiazide on saliva flow rate and composition

Aim of this study was to evaluate the effect on saliva flow rate and composition and on perceived xerostomia. The study used a Latin square design, all subjects being once daily (at 7.00 a.m.) taking the bendroflumethiazide (2.5 mg), furosemide (40 mg), or placebo, in a randomised order. Each treatment period of 7 days was separated by wash-out periods of 14 days. Unstimulated and paraffin chewing stimulated whole saliva, and 3% citric acid stimulated parotid and submandibular-sublingual secretion were collected twice daily, at 7.30 a.m., with the patients in a fasting condition (morning values), and at 10.30 a.m., about 2 h after intake of a standard breakfast (lunchtime values), on day 0 (baseline), day 1 (acute treatment), and day 7 (chronic treatment). Saliva flow rates were measured and all four secretions were analysed for the concentration of sodium, potassium, chloride, and total protein. Xerostomia was assessed by means of a Visual Analogue Scale. Statistical analysis used the Wilcoxon signed rank test. For flow rate, only that of submandibular-sublingual secretion was affected, significantly so in the morning during chronic treatment with both drugs. In resting whole saliva the output of both sodium and chloride tended to decrease especially during treatment with bendroflumethiazide, while in submandibular-sublingual secretion the output of all the electrolytes was decreased, especially for potassium and chloride and during treatment with furosemide. Further, xerostomia tended to increase during treatment with furosemide, statistically significant at lunchtime during chronic treatment. In conclusion, this study has demonstrated a modest effect on salivary flow rate and a more pronounced effect on saliva composition, especially in submandibular-sublingual secretion during treatment of healthy volunteers with therapeutic doses of two different diuretics, encouraging clinical studies in hypertensive patients and basic research as to the presence of a thiazide sensitive Na-Cl cotransporter in human salivary glands.     

Experimental salivary pellicles formed on the surface of self-curing resin

The aim of this study was to identify the salivary components present in the pellicles formed on self-curing resin and to investigate the qualitative variations in adsorbed salivary pellicle compositions according to different exposure time to saliva. Experimental pellicles were formed by the incubation of polymerized resin particles with fresh human parotid or submandibular-sublingual saliva for either 20 min or 2 h. Pellicles were extracted using formic acid and lyophilized, they were then subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblotting to identify the adsorbed salivary components. The amino acid profiles of the 2 h-pellicles were analysed and compared with those of fresh glandular salivas. There was a difference in the 2 h-pellicle components on the self-curing resin compared with those of other dental materials as well as tooth enamel. The amino acid profiles of the 2 h-pellicles were also different from those of fresh glandular salivas. In the case of submandibular-sublingual saliva, the components of the 2 h-pellicle showed a different pattern compared with those of the 20 min-pellicle. However, there was no significant difference between the components of the 2 h- and 20 min-pellicles in the case of parotid saliva. A distinct difference was found in the surface binding affinities of immunoglobulin (IgA) from different glandular salivas. The findings of this study provide information concerning the initial bacterial adhesion on the surfaces of self-curing resin.     

Salivary anti-candidal assays

Inhibition of Candida albicans blastospore viability by parotid, submandibular-sublingual and whole salivas could not be determined by direct assay of yeast cells in each respective saliva. Determination of antifungal activity could, however, be carried out if saliva was first preincubated with Candida cells and this was immediately followed by removal of saliva and resuspension of yeast cells in nonenriched buffers of pH 5-7 for appropriate incubation periods. To attain accurate reproducible quantitative data, parotid, submandibular-sublingual and whole salivas each required different preincubation times with C. albicans as well as prior acidification and boiling. Acidification was also necessary for optimizing the germ tube assay although, in contrast to blastospore viability, inhibition of blastospore-germ tube conversion could be determined directly in saliva. Salivary antifungal effects on blastospore division were negligible at yeast cell concentrations greater than 10(6) colony-forming units per ml and were found to be independent of pH, whereas salivary inhibition of germ tube formation was significant only at pH 5 in the assay systems employed. The requirement for acidification and an observed enhancement of antifungal activity on aqueous dilution of the saliva suggested that only a fraction of the salivary antifungal components present in saliva were available in the free form to exert their biological activity. These results open up the possibility of investigating salivary antifungal activity in human health and disease.     

Stress response to surgical procedures in the submandibular region and its influence on salivary secretion in mice

Saliva stimulated by pilocarpine was collected from the mouths of adult ICR male mice after either submandibular-sublingual gland (SM-SL) exposure and SM-SL removal under pentobarbital anaesthesia. Salivary flow rates decreased and salivary protein concentrations increased after both surgical procedures. Serum cortisol was elevated after the operations. Salivary protein separation patterns on sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) from surgically treated animals were very similar to those from mice given an alpha 1-adrenergic agonist (phenylephrine), but differed significantly from those given a beta-adrenergic agonist (isoproterenol). When the SM-SL was completely removed (i.e. parotid saliva), protein concentrations also dramatically increased. The SDS-PAGE protein separation pattern in the mice whose SM-SL had been removed was very similar to that in those whose SM-SL had been exposed. Hence, a surgical insult in the submandibular region in mice enhances the secretion of salivary protein, mainly in response to alpha 1-adrenergic receptor stimulation in the parotid gland. This study suggests the usefulness of alpha 1-adrenergic receptor-stimulated parotid salivary protein as a marker of surgical insult.     

Salivary anti-candidal assays

Inhibition of Candida albicans blastospore viability by parotid, submandibular-sublingual and whole salivas could not be determined by direct assay of yeast cells in each respective saliva. Determination of antifungal activity could, however, be carried out if saliva was first preincubated with Candida cells and this was immediately followed by removal of saliva and resuspension of yeast cells in nonenriched buffers of pH 5-7 for appropriate incubation periods. To attain accurate reproducible quantitative data, parotid, submandibular-sublingual and whole salivas each required different preincubation times with C. albicans as well as prior acidification and boiling. Acidification was also necessary for optimizing the germ tube assay although, in contrast to blastospore viability, inhibition of blastospore-germ tube conversion could be determined directly in saliva. Salivary antifungal effects on blastospore division were negligible at yeast cell concentrations greater than 10⁶ colony-forming units per ml and were found to be independent of pH, whereas salivary inhibition of germ tube formation was significant only at pH 5 in the assay systems employed. The requirement for acidification and an observed enhancement of antifungal activity on aqueous dilution of the saliva suggested that only a fraction of the salivary antifungal components present in saliva were available in the free form to exert their biological activity. These results open up the possibility of investigating salivary antifungal activity in human health and disease.     

Effects on salivary flow rate and composition of withdrawal of and re-exposure to the β1 -selective antagonist metoprolol in a hypertensive patient population

Secretion rates and composition of unstimulated and chewing–stimulated whole saliva and 3% citric acid stimulated parotid and submandibular-sublingual secretions were studied in 12 hypertensive patients during withdrawal of and re-exposure to antihypertensive pharmacotherapy. All the patients' blood pressures were well controlled by monotherapy with metoprolol, a β₁-selective adrenoceptor antagonist. Blood pressure measurements and saliva sampling were performed at about 9.30 a.m., 2 h after intake of breakfast, on days 0 (medicated baseline), 7, 14, 28 (nonmedicated experimental values and nonmedicated baseline) and 35 (medicated experimental values). A significant increase in unstimulated whole saliva secretion rate was observed when metoprolol was withdrawn and a corresponding decrease when the drug was reintroduced. A positive correlation was found between diastolic blood pressure levels and chewing-stimulated whole saliva secretion rates. In unstimulated whole saliva and 3% citric acid stimulated submandibular-sublingual secretion, the output of total protein, amylase, potassium, calcium and phosphate was significantly increased during the withdrawal period and decreased when metoprolol was reintroduced. For chewing-stimulated whole saliva, the corresponding changes were restricted to output of total protein and amylase while for citric acid stimulated parotid secretion, no changes in salivary composition were observed. Finally, in all secretions one or both of the ratios hexosamine/total protein and sialic acid/total protein were affected, indicating a possible effect of (J-adrenoceptor antagonists on salivary protein synthesis.     

The effects of electrostimulation on parotid saliva flow: a pilot study

OBJECTIVE: Saliva is a critical fluid necessary for oral health. Medications, radiation therapy, and systemic conditions can decrease salivary function and increase a patient's risk for caries and other oral infections. Palliative management of xerostomia includes wetting agents such as ice chips and saliva substitutes. Systemic agents stimulate salivary flow but often have unfavorable side effects. All have met with limited success. The purpose of this study is to assess the effectiveness of transcutaneous electric nerve stimulation (TENS) as a means of stimulating salivary function in healthy adult subjects. STUDY DESIGN: Twenty-two healthy, adult subjects with no history of salivary gland disorder enrolled in the protocol. The TENS electrode pads were placed externally on the skin overlying the parotid glands. Unstimulated saliva was collected for 5 minutes via the Carlson-Crittenden cup into preweighed vials using standardized collection techniques. The TENS unit was then activated and stimulated saliva collected for an additional 5 minutes. RESULTS: Fifteen of 22 subjects demonstrated increased parotid salivary flow when stimulated via the TENS unit. Five experienced no increase and 2 experienced a decrease. The mean unstimulated salivary flow rate was 0.02418 mL/min (SD 0.03432) and mean stimulated salivary flow rate was 0.04946 mL/min (SD 0.04328). Statistical analysis of flow rates utilizing the paired t test demonstrated the difference to be statistically significant, P < .001. In 7 subjects with 0 baseline flow, 5 continued to have no flow. CONCLUSIONS: The TENS unit was effective in increasing parotid gland salivary flow in two-thirds of healthy adult subjects. A further study in a cohort of patients with salivary gland disorders is warranted.     

Salivary receptors for the proline-rich protein-binding and lectin-like adhesins of oral actinomyces and streptococci

Colonization of the tooth surface by actinomyces and viridans group streptococci involves the attachment of these bacteria to adsorbed salivary components of the acquired enamel pellicle. The hypothesis that this attachment depends on specific adhesins has now been assessed from the binding of bacteria with well-defined adhesive properties to blots of SDS-PAGE-separated parotid and submandibular-sublingual (SM-SL) saliva. Streptococcus sanguis and type 2 fimbriated Actinomyces naeslundii, which bound terminal sialic acid and Galbeta1-3GalNAc, respectively, recognized only a few SM-SL salivary components, primarily MG2. In contrast, type 1 fimbriated A. naeslundii and S. gordonii, which bound purified proline-rich proteins (PRPs), recognized several other components from both SM-SL and parotid saliva. Significantly, bacteria that lacked PRP-binding and the lectin-like activities detected by binding to MG2 failed to bind any immobilized salivary component. These findings suggest the involvement of specific adhesins in bacterial recognition of many adsorbed salivary proteins and glycoproteins.     

Identification of salivary proteins inhibiting herpes simplex virus 1 replication

Salivary proteins play an important role in the maintenance of the oral ecology. Previous studies have indicated that human submandibular-sublingual and parotid salivas can selectively suppress the in vitro infectivity of herpes simplex virus 1. The purpose of this study was to identify the salivary components in human submandibular-sublingual saliva that modulate in vitro infectivity. Assessment of the interaction of viral particles with salivary components was accomplished using an in vitro solid-phase assay. These experiments revealed that herpes simplex virus particles selectively interact with the members of the salivary proline-rich protein and cystatin families. Subsequent yield reduction assays demonstrated the ability of proline-rich proteins and salivary cystatins to inhibit the viral replication, with basic proline-rich peptides being more effective. Subsequent assays suggest that basic proline-rich peptides reduced the virus titer by interfering with penetration and/or cellular processing of virus within the target cell. Collectively, these results further suggest that salivary proteins have an important role in the host defense mechanism against recurrent herpesvirus infection.     

Levels of pre-kallikrein in resting and stimulated human parotid and submandibular saliva

Salivary tissue kallikrein is stored in an active form in human salivary glands. Pre-kallikrein has been demonstrated in mixed saliva, but it is not clear if the various salivary glands contribute equally. This study set out to determine if pre-kallikrein is present in human parotid and submandibular salivas at rest, whether levels change during stimulation, and to compare the pattern of pre-kallikrein and kallikrein secretion with that of total protein. Resting and citric acid-stimulated parotid and submandibular, and gum-stimulated parotid saliva samples were collected from 6 healthy subjects. Salivary flows were determined gravimetrically. Total protein concentration and kallikrein enzymic activity were assayed using standard techniques. Pre-kallikrein was assayed following trypsinisation of duplicate samples. Pre-kallikrein was present in parotid and submandibular ductal saliva. Proportions of pre-kallikrein and active kallikrein were similar in salivas secreted at rest and during stimulation, and both outputs mirrored protein output in both major glands. Gum-stimulated parotid saliva showed lower activity than resting, and no differences were seen between resting and stimulated submandibular samples.     

Preliminary proton nuclear magnetic resonance studies of human saliva

Summary-Proton NMR spectra of gustatory stimulated healthy human whole, parotid and submandibular and sublingual saliva were measured. The typical patterns of their spectra were obtained. Among these three kinds of fluids the parotid saliva which contains preferentially serous saliva presented a relatively well resolved spectrum with satisfactory signal to noise ratio in a given short time(30min.). For eight subjects of parotid saliva collected in the afternoon the marked increase in signal intensity in the methyl and methylene proton region of proteins(peptides)was observed as compared with those collected in the morning, reflecting the circadian rhythms in the protein concentration in saliva. On the other hand the methyl peak of lactic acid presented the opposite tendency, which might be also correlated with the circadian rhythms of the glucose metabolism of the parotid gland. The proton NMR spectra of three patients suspected of salivary gland disease were different from those of healthy subjects.     

Stimulated parotid salivary flow rate in patients with Down syndrome

Saliva is essential for oral defense against infections. Decreased salivary secretion may result in increased dental caries, oral mucosal changes, an altered sense of taste, difficulty in swallowing, and oral pain. A review of the literature reveals sporadic and contradictory reports on the use of sialometry and sialochemistry to explain the role of saliva in the oral health and well‐being of subjects with Down syndrome. The present study documents parotid gland saliva secretion at different ages in a group of subjects with Down syndrome. Saliva was collected from 39 patients 11 to 62 years old, by means of a parotid salivary gland cup and under standardized conditions of stimulated secretion. The rate of salivary secretion in the entire group of patients with Down syndrome was lower than that of healthy controls and lower in the older study group compared with the younger group. Institutionalized subjects or those living in hostellike apartments had a lower secretion rate than those living at home. No difference in salivary flow was found between those patients with Down syndrome with normal thyroid output and those with hypothyroidism who were receiving replacement therapy. In a four‐way ANOVA with flow as the dependent variable and Down syndrome, hypothyroidism, institutionalization, and age as factors, Down syndrome was found to be the only variable significantly related to flow (p = 0.017). Our findings indicate that stimulated parotid salivary hypofunction in Down syndrome subjects is mainly related to their genetic disorder.     

Minor salivary gland secretion rates and immunoglobulin A in adults and the elderly

Previously published data are conflicting about the effect of various factors on secretions from minor salivary glands. The aim of the present study was to investigate the secretion rate from palatal, buccal, and labial glands, and to analyze the immunoglobulin A (IgA) concentrations in relation to age, gender, circulatory disease, diabetes, medication, smoking, and pregnancy. Resting and stimulated whole-saliva secretion rates, as well as IgA concentration in stimulated whole saliva, were also examined. One-hundred and forty two individuals (96 women and 46 men), 18-82 yr of age, participated. The results did not suggest any effect of aging on the secretion capacity of minor salivary glands, but the IgA concentration seemed to increase with age. Women had lower buccal and labial saliva secretion rates, and lower levels of IgA in buccal saliva, than men. For whole saliva, resting, but not stimulated, saliva secretion rates were reduced with age, and the secretion rate of stimulated whole saliva was lower in women than in men. The IgA concentration in buccal saliva showed a positive correlation with IgA in stimulated whole saliva, and the IgA concentration decreased with increased flow rate in both salivas.     

Variability of flow rate when collecting stimulated human parotid saliva

The aim of this study was to estimate the accuracy and reproducibility of citric‐acid‐stimulated parotid saliva sampling. In healthy volunteers a strong correlation (r² = 0.79) between flow rates from the left and right parotid gland was observed. In patients with Sjögren's syndrome this correlation (r² = 0.90) was even stronger. The intraindividual variation in healthy volunteers was 23.3 ± 5.9%. Increasing the number of collections did not reduce this variation significantly. In head and neck cancer patients, to estimate whether repeated measurements result in more reliable baseline values for use in clinical studies, repeated collections did not result in a significant reduction of intrapatient variation, similar to the results with the healthy volunteers. Thus, notwithstanding the good agreement between left and right flow rates, a high variation in parotid flow rates has to be considered when planning clinical trials evaluating the effects of treatment on salivary gland functioning.     

Levels of parotid and submandibular/sublingual salivary immunoglobulin A in response to experimental gingivitis in humans

Salivary secretory IgA (s-IgA) is considered to act as an important first line of defense mechanism in the oral cavity. It has therefore been suggested that an increased antigenic load would induce an increase in salivary IgA production. This study investigated the pure glandular levels of salivary IgA in parotid and submandibular/sublingual (SM/SL) saliva during plaque accumulation leading to experimental gingivitis. Starting from regular oral hygiene, 14 healthy, nonsmoking men refrained from all oral hygiene measures for 12 days. On days –2, 0, 3, 6, and 12 a plaque index, a bleeding index, and unstimulated and stimulated saliva from the parotid and the SM/SL glands were measured. Salivary IgA was quantified using a sandwich ELISA. All subjects developed gingivitis as measured by a bleeding index. Compared to baseline the salivary flow rate was increased on day 12. Regarding the secretion rate of IgA there was a statistically significant increase in stimulated parotid saliva but not SM/SL saliva compared to baseline after 6 and 12 days without oral hygiene. No significant changes were observed for the concentration of IgA during the trial. Thus, in healthy subjects with regular oral hygiene the development of plaque induced gingivitis is associated with increased salivary gland output and increased total IgA output levels in stimulated parotid saliva but not in SM/SL saliva.     

The relationship between salivary histatin levels and oral yeast carriage

Candida species are common commensal inhabitants of the oral cavity. Human saliva contains antifungal proteins called histatins. We tested the hypothesis that oral yeast status is related to salivary histatin levels. Thirty subjects were divided into two groups based on the presence (n = 15) or absence (n = 15) of yeast on oral mucosa surfaces. Unstimulated and stimulated submandibular and sublingual and parotid saliva was collected from each subject. Salivary flow rates were measured and histatin concentrations were determined in the stimulated saliva samples. The yeast colony positive group showed lower median unstimulated parotid saliva flow rates as well as lower median concentrations of total histatins in submandibular and sublingual saliva. There was a negative correlation between yeast colony-forming units and unstimulated parotid saliva flow rates and between yeast colony-forming units and submandibular and sublingual saliva histatin concentration and secretion. The results suggest that oral yeast status may be influenced by unstimulated parotid saliva flow rates and by submandibular and sublingual histatin concentration and secretion.     

Immunochemical analysis of high molecular-weight human salivary mucins (MG1) using monoclonal antibodies

Using four Mabs with different specificities for salivary mucins, an ELISA has been developed in which human whole saliva, glandular salivas, salivary protein fractions and purified, high molecular-weight, mucin fractions (MG1) isolated from human submandibular and sublingual glandular tissues have been immunochemically analysed. All four Mabs reacted with MG1s. Three of them reacted with the purified, low molecular-weight salivary mucins (MG2). None was reactive with parotid saliva. MG1 preparations isolated from submandibular and sublingual glandular tissues of one and the same individual displayed different patterns of reactivity with these Mabs, indicating that they differ immunochemically. Analysis of the MG1s in salivas derived from individual salivary glands showed differences in immunochemical composition. These results indicate that the MG1 fraction in human whole saliva consists of several immunochemically different species.     

The effect of food deprivation on the circadian rhythms in flow rate and protein concentration in human parotid saliva

The present experiments were designed to determine whether fasting during the morning would influence the circadian rhythms in the flow rate of unstimulated parotid saliva and in the protein concentrations in unstimulated and stimulated parotid saliva. With normal dietary intake, these rhythms are of high amplitude and show minimum values in the early morning and maximum values in mid-afternoon.Studies on nine individuals, with and without fasting, revealed that fasting had no effect on the circadian rhythm in the flow rate of unstimulated parotid saliva and reduced by only about one third the increase in protein concentration which occurs between 0700 and 1300 hr with normal food intake. Thus the major factor responsible for the circadian rhythm in parotid salivary protein concentration remains uncertain, as does the mechanism for the effect of normal food intake.     

A comparative study of salivary lysozyme in caries-resistant and caries-susceptible adults

Lysozyme concentration was quantitated immunochemically in parotid and submandibular-sublingual saliva of 46 caries-resistant and 17 caries-susceptible adults. There was essentially no difference between the two groups. The concentration of lysozyme was three times higher in the submandibular-sublingual than in the parotid secretion, and was significantly higher in unstimulated submandibular saliva than in secretions stimulated with 1, 2, or 4% citric acid. There were no significant differences in flow rate between caries-resistant and -susceptible subjects. Salivary lysozyme concentration is not a critical determinant of resistance or susceptibility to caries.