The flow-rate-dependent excretion of ionized calcium in pilocarpine-stimulated human submandibular saliva

Analysis of salivary flow rate, biochemical composition, and redox status in orchiectomized spontaneously hypertensive rats

OBJECTIVE

This study aimed to analyze the salivary flow rate, biochemical composition, and redox status in orchiectomized spontaneously hypertensive rats (SHR) compared to normotensive Wistar rats.

DESIGN

Thirty-two young adult male SHR and Wistar (3-months-old) rats were randomly distributed into four groups; either castrated bilaterally (ORX) or underwent fictitious surgery (SHAM) as Wistar-SHAM, Wistar-ORX, SHR-SHAM, and SHR-ORX. Two months beyond castration, pilocarpine-induced salivary secretion was collected from 5-month-old rats to analyze salivary flow rate, pH, buffer capacity, total protein, amylase, calcium, phosphate, sodium, potassium, chloride, thiobarbituric acid reactive substances (TBARs), carbonyl protein, nitrite, and total antioxidant capacity.

RESULTS

The salivary flow rate was higher in the Wistar-ORX compared to the Wistar-SHAM group, while remaining similar between the SHR-SHAM and SHR-ORX groups. ORX did not affect pH and salivary buffer capacity in both strains. However, salivary total protein and amylase were significantly reduced in the Wistar-ORX and SHR-ORX compared to the respective SHAM groups. In both ORX groups, salivary total antioxidant capacity and carbonylated protein were increased, while lipid oxidative damage (TBARs) and nitrite concentration were higher only in the Wistar-ORX than in the Wistar-SHAM group. In the Wistar-ORX and SHR-ORX, the salivary calcium, phosphate, and chloride were increased while no change was detected in the SHAM groups. Only salivary buffering capacity, calcium, and chloride in the SHR-ORX adjusted to values similar to Wistar-SHAM group.

CONCLUSION

Hypertensive phenotype mitigated the orchiectomy-induced salivary dysfunction, since the disturbances were restricted to alterations in the salivary biochemical composition and redox state.

[Effects of acid stimulation on saliva flow rate and compositions of human parotid and submandibular glands]

OBJECTIVE

To investigate the effect of acid stimulation on salivary flow rate and compositions of human parotid and submandibular glands, so as to provide basis for comprehensive evaluation of salivary gland function in both health and disease status.

METHODS

In the study, 210 healthy participants' whole saliva samples were collected under passive drooling, and their parotid gland and submandibular gland secretions were collected by negative pressure suction. 2% citric acid was dropped on the tip of tongue every 1 min for acid stimulation for a total of 5 times to collect stimulated whole saliva, parotid and submandibular gland saliva. The collected saliva was weighed and saliva flow rate was calculated. The K⁺, Na⁺, Cl^-, Ca²⁺, total protein, total phosphorus and α-amylase in saliva samples were detected by biochemical analyzer, and the changing features of flow rate and compositions of different kinds of saliva were compared and analyzed.

RESULTS

After acid stimulation, saliva flow rate significantly increased. The increase proportion of parotid gland saliva (10.7 folds) was much higher than that of submandibular gland saliva (2.9 folds). The concentrations of Na⁺, Cl^-, Ca²⁺, total protein and α-amylase in parotid gland saliva increased significantly (P < 0.05), but there was no significant difference in total phosphorus and K⁺ (P=0.89, P=0.34). The concentration of Na⁺ and Ca²⁺ in saliva of submandibular gland increased significantly(P < 0.05), the concentration of total phosphorus decreased significantly(P < 0.05), and the concentration of Cl^- increased, but the difference was not significant(P=0.068). There was no significant difference in total protein, K⁺ and α-amylase (P=0.85, P=0.07, P=0.95). The compound secretion rate of total phosphorus in saliva of submandibular gland remained unchanged(P=0.066), while the secretion rate of K⁺, Na⁺, Cl^-, Ca²⁺, total protein and α-amylase significantly increased(P < 0.01). The compound secretion rate of K⁺, Na⁺, Cl^-, Ca²⁺, total protein and total phosphorus and α-amylase in parotid gland saliva increased(P < 0.01). The concentrations of Na⁺, Cl^-, K⁺, total phosphorus, total protein and α-amylase in parotid were higher than those in submandibular gland (P < 0.01), and the concentration of Ca²⁺ in submandibular gland saliva was significantly higher than that in parotid (P < 0.001).

CONCLUSION

The response of parotid to acid stimulation is stronger, and the secretion of submandibular gland is more stable. Acid stimulation significantly influences the concentrations of electrolytes in saliva, and the composited secretion rate is an evaluation index to reflect both flow rate and composition concentration of saliva. The parotid gland plays an important role in the secretion of total protein, total phosphorus and α-amylase in saliva, and the submandibular gland is the main source of Ca²⁺ in saliva.

Comparison of Salivary Calcium Level in Dentulous and Edentulous Patients

OBJECTIVES

Calcium is an inorganic component of the saliva, which is especially important in oral and dental health. This study sought to compare unstimulated salivary calcium level of dentulous and edentulous patients.

MATERIALS AND METHODS

This case-control study was conducted on 72 participants, including 36 dentulous and 36 edentulous patients. The unstimulated salivary flow rate of patients and the mean salivary calcium concentration were measured and compared. The data were analyzed using the nonparametric Mann-Whitney U-test.

RESULTS

The mean age of participants was 56.3 years. The mean number of teeth was 18.9 in the dentulous group. No significant difference was noted in salivary calcium level of dentulous and edentulous patients. The mean salivary calcium concentration was 0.61 ± 0.3875 mmol/L in dentulous and 0.8025 ± 0.5975 mmol/L in edentulous patients. Salivary calcium level had a significant inverse correlation with salivary flow rate (r = -0.370, p = 0.027), and by every 1-unit increase in salivary flow rate, salivary level of calcium significantly decreased by 3.85 units.

CONCLUSION

Edentate had averagely higher salivary calcium level compared to dentulous. The salivary concentration of calcium ion is not correlated to the presence or absence of teeth. Salivary flow rate reduces the calcium concentration.

Age changes in secretory function of male and female rat parotid glands in response to methoxamine and pilocarpine

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of both parotid glands of male and female rats at weekly age intervals from three to 10 weeks, and at 3.5, 8, and 15 months of age. It was analyzed for the concentrations of protein, potassium, calcium, inorganic phosphate, and for amylase activity. The type of protein were determined electrophoretically, and an amino acid analysis of the total protein was also carried out. The wet weights of the glands increased substantially up to eight weeks of age, then reached almost plateau values, and finally tended to decrease at 15 months of age in both sexes. The salivary volumes secreted in response to methoxamine and pilocarpine were positively correlated with the parotid gland weights in both sexes. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the salivary flow rates only at relatively low rates of flow. The amylase activity was positively correlated with the concentration of protein, independent of the nature of the stimulus, age, and sex. With methoxamine as a stimulus, the amylase activity was positively correlated with the concentration of calcium, independent of age and sex. The types of protein and amino acid concentrations were independent of the nature of the stimulus, age, and sex up to 15 months of age. However, in parotid saliva of several rats at 8 and 15 months of age, unusual proteins were observed electrophoretically, independent of the nature of the stimulus and sex.

Developmental changes in the volumes, protein, and some electrolyte concentrations of male and female rat submandibular saliva secreted in response to methoxamine and pilocarpine

Saliva secreted in response to methoxamine and pilocarpine was collected from the cannulated ducts of the submandibular glands of male and female rats at weekly intervals from two to 10 weeks of age. It was analyzed for volume and for concentrations of protein, potassium, calcium, and inorganic phosphate. Following the collection of saliva, the submandibular glands were removed and weighted. The wet weights of the glands increased substantially up to seven weeks of age and then reached almost plateau values in both sexes. The salivary volumes secreted in response to both agents in both sexes were positively correlated with the gland weights, except that after five to six weeks of age there was no correlation between gland weight and methoxamine-stimulated salivary volume. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the flow rates only at relatively low rates of flow. The concentration of calcium was positively correlated with the protein concentration and was independent of the nature of the stimulus and of sex differences during postnatal development.