Salivary Electrolyte Concentrations Research Articles

Salivary parameters and periodontal inflammation in obstructive sleep apnoea patients

The aim of this cross-sectional study was to objectively assess the salivary flow rate and composition and periodontal inflammation in obstructive sleep apnoea (OSA) patients. The subjects, who underwent whole-night polysomnography or polygraphy, were referred for saliva sampling and periodontal examination. According to the severity of OSA based on the Apnoea Hypopnea Index (AHI) value, the subjects were classified into groups: no OSA (AHI < 5; N = 17), mild to moderate OSA (AHI 5–29.9; N = 109), and severe OSA (AHI > 30; N = 79). Salivary flow rate, pH, salivary electrolytes, and cortisol were measured from collected saliva samples. Periodontal examination included assessment of the number of teeth, dental plaque, bleeding on probing and periodontal measurements: gingival recession, probing pocket depth, clinical attachment level (CAL) and periodontal inflamed surface area (PISA) score. There were no significant differences in salivary flow rate, salivary pH, salivary electrolyte concentrations or electrolyte ratios among the groups classified according to the severity of OSA. However, subjects without OSA had higher salivary cortisol concentrations than OSA groups (p < 0.001). Increased plaque scores were associated with a higher AHI (r = 0.26; p = 0.003). According to the salivary flow rate, subjects with hyposalivation and reduced salivation had higher concentrations of salivary electrolytes and lower salivary pH than subjects with normal salivation. Subjects with hyposalivation had an increased Mg/PO4 ratio (p < 0.001) and a reduced Ca/Mg ratio (p < 0.001). Furthermore, subjects with severe OSA tended to have higher CALs and plaque volumes. In conclusion, under pathological conditions, such as OSA, multiple interactions might impact salivary flow and electrolyte composition. Complex interrelationships might affect the integrity of oral health, especially considering OSA severity, inflammation, concomitant diseases and medications.

Changes in salivary electrolyte concentrations in mid-distance trained sled dogs during 12 weeks of incremental conditioning.

Regular exercise improves the health status of dogs; however, extreme exertion in the absence of adequate fluid and electrolyte replacement may negatively impact health and performance due to dehydration and cardiovascular stress. Unlike humans and horses, dogs thermoregulate predominantly through respiration and salivation, yet there is a dearth of literature defining exercise‐induced changes to canine salivary electrolytes. The study objective was to investigate the effects of exercise on salivary electrolyte concentrations, and to determine if adaptations may occur in response to incremental conditioning in client‐owned Siberian Huskies. Sixteen dogs were used, with an average age of 4.8 ± 2.5 years and body weight of 24.3 ± 4.3 kg. A 12‐week exercise regimen was designed to increase in distance each week, but weather played a role in setting the daily distance. Saliva samples were collected at weeks 0 (pre‐run, 5.7 km), 5 (pre‐run, 5.7, 39.0 km), and 11 (pre‐run, 5.7, 39.0 km). Samples were analyzed for sodium, chloride, potassium, calcium, magnesium, and phosphorous using photometric and indirect ion‐selective electrode analysis. When compared across weeks, sodium, chloride, potassium, and calcium concentrations did not differ at any sampling time point; however, phosphorus and magnesium concentrations increased from baseline. Data were then pooled across weeks to evaluate changes due to distance and level of conditioning. Sodium, chloride, and magnesium concentrations increased progressively with distance ran, suggesting that these electrolytes are primarily being lost as exercising dogs salivate. Repletion of these minerals may assist in preventing exercise‐induced electrolyte imbalance in physically active dogs.

246 Salivary electrolyte turnover in mid-distance trained sled dogs during 12 weeks of incremental conditioning

Abstract Regular exercise improves the health status of dogs; however, extreme exertion in the absence of adequate fluid and electrolyte replacement may decrease performance due to dehydration and cardiovascular stress. Unlike humans and horses, exercising dogs thermoregulate predominantly through respiratory and salivary losses, yet there is limited literature defining changes due to exercise in canine salivary electrolytes. The objective was to investigate the effects of a stepwise exercise regimen on salivary electrolyte concentrations in sled dogs. A training regimen was implemented whereby exercise intensity and duration increased incrementally over 12 weeks and was only altered due to inclement weather. Using sterile gauze and forceps, saliva samples were collected from 16 client owned Siberian Huskies at week-0 (pre-run, post-5.7km-run), week-6 (pre-run, 5.7km, post-39km-run), week-12 (pre-run, 5.7km, post-39km-run). Samples were analyzed for sodium, chloride, potassium, calcium, magnesium, and phosphorous using photometric and indirect ion-selective electrode analysis. Data were analyzed using PROC MIXED of SAS (v.9.4; SAS Institute Inc., Cary, NC). Means were separated using the Tukey adjustment. When compared across weeks, sodium, chloride, potassium, and calcium did not differ at any sampling time point. Throughout the 12 weeks, pre-run and 5.7km phosphorus, and 5.7 and 39km magnesium had increased (P &amp;lt; 0.05). Data were then pooled to evaluate changes due to run distance. Pre-run calcium and phosphorus was higher than at 5.7 and 39km (P &amp;lt; 0.05). Magnesium at 39km was greater than 5.7km, and at 5.7km was greater than pre-run (P &amp;lt; 0.05). Pre-run sodium was lower than at 5.7 and 39km (P &amp;lt; 0.05). Chloride at 5.7km was similar to pre-run and 39km, and at 39km was greater than pre-run (P &amp;lt; 0.05). These data suggest that as dogs become conditioned, they do not employ mechanisms to conserve salivary electrolytes, and that an electrolyte supplement with magnesium, sodium and chloride could be beneficial for sporting dogs.

Calcium, vitamin D supplements with or without alendronate and supragingival calculus formation in osteoporotic women: a preliminary study

Objectives: Long-term calcium intake is related to the formation of urinary stones. Structure and composition of kidney and gallstones are similar to dental calculus. Saliva is the source of calcium for supragingival dental calculus formation. The aim of this preliminary study was to evaluate the possible effects of long-term calcium and vitamin D supplementation with or without alendronate administration on salivary electrolyte concentrations and supragingival calculus formation in osteoporotic women. Methods: Thirty-one female patients with osteoporosis for at least 3 years participated in this study. Eighteen women were taking calcium plus vitamin D plus alendronate, while 13 women were taking only calcium plus vitamin D supplements. Eleven systemically healthy women volunteered for the control group. Whole saliva samples were collected from all women before initiation of any periodontal intervention. Plaque index, probing depth, clinical attachment level, bleeding on probing, and calculus index were recorded at six sites/tooth. Salivary concentrations of ionic calcium, potassium, magnesium and sodium were determined by atomic absorption spectrophotometer. Results were evaluated statistically by non-parametric tests. Results: No significant differences were found in clinical parameters or results of saliva analysis between the study groups (p > 0.05). Conclusion: Within the limits of this preliminary study, it is suggested that long-term calcium and vitamin D supplementation with or without alendronate does not appear to have a significant effect on supragingival calculus formation or saliva total calcium, potassium, magnesium and sodium concentrations. Larger-scale studies investigating the possible effects of various treatment modalities of osteoporosis on supragingival calculus formation are required to better clarify this issue.

Review: The physiology of saliva and transfer of drugs into saliva

Although saliva or oral fluid “lacks the drama of blood, the sincerity of sweat and the emotional appeal of tears”, quoting Mandel in 1990 [I.D. Mandel, The diagnostic uses of saliva, J. Oral Pathol. Med. 19 (1990) 119–125], it is now meeting the demand for inexpensive, non-invasive and easy-to-use diagnostic aids for oral and systemic diseases, drug monitoring and detection of illicit use of drugs of abuse, including alcohol. As the salivary secretion is a reflex response controlled by both parasympathetic and sympathetic secretomotor nerves, it can be influenced by several stimuli. Moreover, patients taking medication which influences either the central nervous system or the peripheral nervous system, or medication which mimic the latter as a side effect, will have an altered salivary composition and salivary volume. Patients suffering from certain systemic diseases may present the same salivary alterations. The circadian rhythm determines both the volume of saliva that will and can be secreted and the salivary electrolyte concentrations. Dietary influences and the patient's age also have an impact on composition and volume of saliva. The latter implies a wide variation in composition both inter- and intra-individually. Sampling must therefore be performed under standardized conditions. The greatest advantage, when compared to blood sample collection, is that saliva is readily accessible and collectible. Consequently, it can be used in clinically difficult situations, such as in children, handicapped and anxious patients, where blood sampling could be a difficult act to perform.

The effects of prolonged gum chewing on salivary flow rate and composition

Objective: To determine the effect of gum chewing for 2 h on salivary flow rate and composition. Design: Five male and five females each collected whole saliva at intervals over a 2 h period on three separate days, prior to which they collected unstimulated saliva for 5 min. For one 2 h session they continued to collect only unstimulated saliva while for the others one tablet of Wrigley’s Extra peppermint- or fruit-flavoured (peach) gum was chewed continuously. Flow rates were calculated and the saliva was assayed for pH and for Na, K, Ca, Cl, inorganic P and protein concentrations. The data were subjected to repeated-measures ANOVA and Duncan tests. Results: When only unstimulated saliva was collected, there was no significant change in salivary flow rate over the 2 h. With the chewing gums the flow rate increased initially and then, after 35–40 min, fell to similar plateau values which remained significantly higher than the initial unstimulated flow rate and significantly higher than the flow rate at the corresponding time intervals when only unstimulated saliva was collected. With both gums the salivary pH from 2 min to 2 h was significantly higher than that of unstimulated saliva. The changes in the salivary electrolyte and protein concentrations due to the flow rate increase elicited by the chewing gum were largely as expected from previous studies on parotid and submandibular saliva. Conclusion: During prolonged chewing gum use, both salivary flow rates and pH remained significantly above the values for unstimulated saliva.

Salivary electrolyte concentrations are associated with cystic fibrosis transmembrane regulator genotypes.

It is estimated that about one in 24 Belgian Caucasians is a cystic fibrosis (CF) heterozygote. Until now, CF heterozygotes can only be identified by genetic decoding (e.g. Inno-Lipa CF2 test), as they cannot be phenotypically distinguished from the general population. The aim of this study was to evaluate differences in salivary electrolyte concentrations (calcium, bicarbonate, chloride, potassium, sodium and phosphate) and salivary osmolarity between CF homozygotes (n=41), CF heterozygotes (n=56) and healthy controls (n=65). Differences between the three groups were investigated by means of non-parametric tests. Several significant differences between the three study groups and among, as well as between, the different cystic fibrosis transmembrane regulator (CFTR) genotypes were observed. Significant differences in salivary electrolyte concentrations between individuals with delta F508 mutation and those without, and between CF homozygotes and heterozygotes were observed. The concentrations of several salivary electrolytes, and salivary osmolarity were significantly higher in CFTR genotype individuals. Differences in salivary electrolyte concentrations may partly explain differences in caries between the three study groups.

Salivary secretion during selective beta-adrenoreceptor stimulation and blockade in the parotid gland of red kangaroos, Macropus rufus.

Intracarotid infusions of noradrenaline (0.3 nmol.kg(-1) x min(-1)) stimulated salivary fluid secretion and caused increases in salivary concentrations of protein, potassium. magnesium. chloride and phosphate, and decreases in bicarbonate. These effects of intracarotid noradrenaline were not reduced by simultaneous intracarotid infusion of phentolamine (3.0 nmol.kg(-1) x min(-1)) but were significantly greater than the responses accompanying intravenous noradrenaline infusion. Concomitant administration of the beta-antagonist, CGP20712A, were much more effective in blocking the noradrenaline-induced changes in salivary composition than equimolar infusions of the beta2-antagonist, ICI118551, thereby confirming the presence of beta1-adrenoreceptors. Intracarotid infusion of salbutamol at 0.6 nmol x kg(-1) x min(-1) and 6.0 nmol x kg(-1) x min(-1) caused increasing but qualitatively similar changes in salivary composition to intracarotid noradrenaline but was less effective than noradrenaline in augmenting salivary protein release. Equimolar intravenous infusions of salbutamol and noradrenaline were equally potent in altering salivary electrolyte concentrations but salbutamol by this route had less effect on protein release and fluid secretion. Concurrent intravenous and intracarotid infusions of beta1-(CGP) and beta2-(ICI) antagonists with intracarotid salbutamol showed that the beta2-antagonist was more potent than the beta1-antagonist by the intracarotid route thereby demonstrating the presence of glandular beta2-receptors and eliminating the possibility that the response to salbutamol was due totally by reflex increases in general sympathetic tone triggered by lowered blood pressure. It was concluded that the kangaroo parotid has functional beta1- and beta2-adrenoreceptor subtypes in endpieces whereas the data provide little support for either adrenoreceptor subtype being present in the excurrent duct system.

Use of Human Minor Salivary Glands in Basic and Applied Secretion Research

Previous findings from studies utilizing human labial and palatine minor salivary glands are reviewed. These studies took histopathological, biochemical, and ultrastructural approaches, and focused on control and diseased glands. Disease-oriented summarizations are used, and control results are discussed in the context of disease-related findings. Findings are reviewed separately for electrolytes, macromolecules, and ultrastructure. In control subjects, minor gland salivary electrolyte concentrations are dependent on flow rate, and this dependence may be altered by diseases such as cystic fibrosis as-well as by inflammatory situations such as graft-versus-host disease. There is also evidence that salivary electrolyte secretion processes are not similar in labial and palatine minor glands. Studies of salivary macromolecular composition are reviewed for control subjects and for patients with graft-versus-host disease and Sjögren's syndrome. The findings indicate that the macromolecular contents of labial and palatine gland saliva are similar, but that both are significantly different from that for major gland saliva. Finally, studies attempting to measure disease-related changes in intracellular composition are reviewed. It is concluded that the minor salivary glands are important models for the study of exocrine gland physiology and pathophysiology in man.

Use of human minor salivary glands in basic and applied secretion research.

Previous findings from studies utilizing human labial and palatine minor salivary glands are reviewed. These studies took histopathological, biochemical, and ultrastructural approaches, and focused on control and diseased glands. Disease-oriented summarization are used, and control results are discussed in the context of disease-related findings. Findings are reviewed separately for electrolytes, macromolecules, and ultrastructure. In control subjects, minor gland salivary electrolyte concentrations are dependent on flow rate, and this dependence may be altered by diseases such as cystic fibrosis as well as by inflammatory situations such as graft-versus-host disease. There is also evidence that salivary electrolyte secretion processes are not similar in labial and palatine minor glands. Studies of salivary macromolecular composition are reviewed for control subjects and for patients with graft-versus-host disease and Sjögren's syndrome. The findings indicate that the macromolecular contents of labial and palatine gland saliva are similar, but that both are significantly different from that for major gland saliva. Finally, studies attempting to measure disease-related changes in intracellular composition are reviewed. It is concluded that the minor salivary glands are important models for the study of exocrine gland physiology and pathophysiology in man.

The chronically reserpinized rat as a model for cystic fibrosis: alterations in the mucus-secreting sublingual gland.

Summary: The chronic administration of reserpine (0.5 mg/kg body weight, daily for 7 days) increases the density of adrenergic receptors in the sublingual gland of the rat. The Bmax values (in pmole/g tissue) were 5.8 ± 0.9 for [3H]-prazosin, 22 ± 4 for [3H]-clonidine and 11.9 ± 1.7 for [3H]-dihydroalpranolol. These radioligands are used, respectively, for the study of α1, α2 and β-adrenergic receptors and the Bmax values indicated are 181, 226, and 331%, respectively, of the corresponding values in control sublingual glands. The increase in the density of α1-adrenregic receptors was accompanied by the development of a clear secretory response to norepinephrine and phenylephrine, as judged by the ability to release K+ in vitro. This response, which was not observed in control sublingual glands, amounted to 21.9 ± 2.5 and 16.8 ± 3.1% of the tissue content of K+, respectively, for the two agonists. Neither the density of muscarinic cholinergic receptors (Bmax = 106% of control value) nor the extent of K+ release elicited by carbamylcholine was modified by the drug treatment, when compared to those observed in control glands. In vivo, the volume of sublingual saliva secreted in response to i.v. infusions of acetylcholine was significantly reduced in the treated animals to 45% of that secreted by control rats. This was accompanied by increases in salivary concentrations of protein-bound carbohydrates, with no change in the individual carbohydrate ratios. No significant changes in salivary electrolyte concentrations (Na+, K+, Ca++) were observed in sublingual saliva of reserpine-treated rats. In summary, reserpine administration alters adrenergic receptor density and sensitivity in the rat sublingual gland and modifies its secretory responses both in vitro and in vivo. The chronic administration of reserpine to rats causes widespread exocrine gland disturbances resembling those of cystic fibrosis. The results of this study show that the drug treatment also affects a mucus-secreting salivary gland and support the view that the reserpine-treated rat is a useful experimental model of the human disease.

Dopamine-induced secretion of protein and of some electrolytes by rat submandibular and parotid glands

The secretory effects of dopamine were tested in Nembutal-anaesthetized adult male Sprague-Dawley rats injected either intraperitoneally (i.p.; 5–100 mg/kg) or intravenously (i.v.; 250 μg-3 mg/kg) and with or without α- and β-adrenergic and cholinergic blockers and haloperidol. Polyacrylamide-disc gel electrophoresis was used to separate the different proteins in parotid and submandibular duct saliva and the latter was also analysed for Na, K, Ca and P. The proteins secreted in parotid saliva were similar to those elicited by α- and β-adrenergic and cholinergic agonists and the effects of dopamine appeared to be similar to those produced by β-adrenergic stimulation. Parotid secretion was partially blocked by both phentolamine and haloperidol, suggesting that dopamine is also acting on α-adrenergic and on specific dopamine receptors. The submandibular gland is able to secrete different types of proteins in response to α-adrenergic agonists (α-type proteins) as opposed to β-adrenergic or cholinergic agonists (β-type proteins). With i.v. dopamine at all doses and i.p. dopamine at doses of 75 mg/kg or above, the proteins secreted by the submandibular glands were of the α-type. However, at i.p. doses of 40 mg/kg or less, proteins of the β-type were secreted. Thus the types of proteins secreted were dose-dependent. Administration of each of six α-adrenergic blockers prior to the higher doses of dopamine caused secretion only of proteins of the β-type, but this change did not occur after administration of atropine, propranolol or haloperidol, although haloperidol partially blocked the secretory effects of dopamine. Despite the difference in types of proteins secreted in response to i.p. dopamine at 40 and 75 mg/kg, the salivary electrolyte and total protein concentrations were not significantly changed.

Salivary electrolyte concentrations and electrical potential difference across the parotid salivary duct of anaesthetized sodium-replete sheep.

Salivary flow rate and the concentrations of electrolytes in parotid saliva and arterial plasma from anaesthetized sodium-replete sheep were measured before, during and after ipsilateral intracaroitd infusion of acetylcholine at 10 nmol min-1 to ascertain whether anaesthesia altered the relation between salivary flow and sodium concentration. The potential difference (PD) between the lumen of the parotid duct and the vascular system was also measured. Concentrations of salivary sodium and phosphate were decreased and potassium concentration and total CO2 content were increased when rate of salivary flow was increased by acetylcholine infusion. Salivary chloride concentration was reduced in five experiments and increased in three experiments when flow rate was elevated. Thus the flow-composition relations of parotid saliva from anaesthetized sheep were essentially the same as those for saliva from conscious animals. The PD between the lumen of the parotid duct and blood at resting flow rates was 9.4 +/- 1.07 mV, lumen negative. At high flow rates, stimulated by acetylcholine infusion, the PD increased to 21.9 +/- 2.20 mV, lumen negative. This increase in PD of the duct epithelium appeared to depend on changes in the composition of saliva arriving at the site of potential measurement.

Clinical Annotation: A Continuous Simultaneous Interdental Suture Technique

RADIATION-INDUCED XEROSTOMIA IN CANCER PATIENTS. EFFECT ON SALIVARY AND SERUM ELECTROLYTES Dreizer, S., Brown, L. R . , Handler, S., and Levy, B. M. Cancer 38: 273, July, 1976. To observe the way ionizing radiations affect the output and pH of saliva in patients with radiosensitive malignancies of the head and neck, 30 patients (ages 7 to 76) with natural dentitions, were moni­ tored for salivary and serum electrolyte concentrations. Previous research showed that human salivary glands in the path of tumor- suppressing ionizing radiation undergo progressive glandular atro­ phy, fibrosis and reduction in output beginning shortly after the initial exposure and intensifying thereafter. The clinical findings were that the salivary pH decreased from 7.01 to 6.83 after 6 weeks of radiation. The average flow rate declined from 1.32 ml/min to 0.22 ml/min in the same period of treatment and reached a mean decline of 83.3% by 6 months postradiation. Dental caries began to be clinically evident by 3 months postradiation when the decrease in saliva production reached a mean decline of 93.4%. University of Texas Dental Science Institute, Houston, Texas 77025. Dr. Jacobo Saad PERIODONTAL CONDITION IN TURKISH RECRUITS Bayirli, G. S., and Curilovic, Z. Comm Dent Oral Epidemiol 4: 25, January, 1976. The periodontal status of 300 Turkish recruits, ages 19 to 22, was evaluated and a modified Ramfjord periodontal index determined. Further, the gingival condition, calculus and plaque present, location and depth of periodontal pockets, mobility of teeth, diastema magni­ tude, and DMFT index were determined. The average PDI was 3.8. Considering the total recruit population, 97.6% suffered from gin­ givitis, 68% of whom showed moderate to severe inflammation of the gingiva without involvement of deeper structures. Heavy deposits of calculus and moderate accumulations of plaque were noted. A relatively low DMFT rate found in the present investigation had little correlation with the plaque index. Wear facets, present in nearly all of those examined, were shallow in 88% of the subjects. Dental Institute, University of Zurich, Plattenstrasse 11, P.O. Box 163, CH- 8028, Zurich, Switzerland. Dr. Teresa Toledo THE ROLE OF COMPLEMENT IN INITIAL GINGIVITIS. I. THE EFFECT OF DECOMPLEMENTATION BY COBRA VENOM FACTOR Kahnberg, K . E . , Lindhe, J., and Attstrom, R . J Periodont Res 11: 269, September, 1976. In four Beagle dogs, gingivitis was induced during an 8-hour period by topical application of an extract of human plaque to the margin of normal gingiva on one side before and on the other side following decomplementation. Colloidal carbon was injected intrave­ nously in a hind leg after 6V2 hours of plaque extract and tissues from the biopsies were examined for carbon in the vascular units beneath the junctional epithelium as well as for leukocytes in the junctional epithelium. An attraction of mononuclear leukocytes and neutrophils in addition to an alteration in the function of the dentogingival vasculature were seen in the normal tissue. In the decomplemented animals the plaque components showed a reduced capacity to influ­ ence vascular function, but nearly the same leukocyte migration into the junctional epithelium. Department of Periodontology, Faculty of Odontology, PACK S-400 33, Gothenburg 33, Sweden. Dr. Jahansah Boroumand

Salivary Electrolytes in Infants Receiving Digoxin

Recent adult studies have suggested an increase in salivary K+ and Ca++ in patients receiving digitalis. In order to investigate this phenomenon in the pediatric patient, whole saliva electrolytes were studied in 32 hospitalized infants (mean age 10 weeks); 17 receiving digoxin (aean digoxin level 2.Ing/ml) and 15 controls. Simultaneous serum electrolytes were also measured. Mean salivary K+ was significantly increased, 25,4±3.7mEq/l in the digitalised infants when compared to controls, 21.6±3mEq/l (p < 01). Mean salivary Ca++ was also elevated in the infants receiving digoxin, 4.3±2.8mEq/l versus controls 3.0±.96mEq/l (p < .05). The K+ x Ca++ product was 111.4±84.0 in infants receiving digoxin and 65.3±27.1 for controls (p < .025). Salivary Na+ was not different in the two groups. Serum K+ was elevated in the group receiving digoxin 5.1±.69 as compared to controls 4.6±.68 (p < .05) but serum Ca++ and Na+ concentration were similar. The mean salivary electrolyte concentrations in control infants and those receiving digoxin were comparable to levels reported for adults. The Increase in K+ concentration in saliva of infants receiving digoxin with no change in salivary Na+ lends support to the hypothesis that the increase in K+ in saliva is due to K+ loss from cells or elevated plasma K+ rather than inhibition of Na+/K+ exchange.

Mono- and divalent electrolyte patterns, pCO 2 and pH in relation to flow rate in normal human parotid saliva.

Abstract In parotid saliva of normal subjects the pH, pCO2 and concentrations of sodium, potassium, calcium, magnesium, bicarbonate and inorganic phosphate were determined continuously after stimulation of salivary secretion by pilocarpine. The electrolyte concentrations showed a marked dependence on salivary flow rate. Sodium, calcium and bicarbonate concentrations and pH increased with increasing flow rate but the concentrations of potassium, magnesium and inorganic phosphate decreased with increasing flow rate. In general salivary electrolyte concentrations showed a tendency to approach plasma concentrations with increasing flow rate with the exception of the salivary magnesium concentration, which fell below its plasma level and bicarbonate which exceeded the plasma concentration. The results will be considered as a basis of further investigations on electrolyte excretion patterns in patients with hormonal and metabolic disturbances.

Electrolyte concentrations in primary and final saliva of the rat sublingual gland studied by micropuncture and catheterization techniques.

The salivary electrolyte concentrations at various secretory rates have been studied in the rat sublingual gland and compared with the concentrations found in acinar-intercalated duct (primary) fluid obtained by micropuncture. The primary fluid had the following composition: [Na]=126±1.6 (S.E.M.,n=39) mEq/l; [K]=11.9±1.2 mEq/l (n=39); [Cl]=99.3±2.3 mEq/l (n=33). The Na and K concentrations differed significantly from those of plasma and from those observed previously in the primary fluid of rat parotid and submaxillary glands. The composition of primary fluid was not altered by carbachol stimulation. After carbachol stimulation, the final saliva, like that of the human but unlike that of the cat and dog sublingual gland, was hypotonic and the electrolyte concentrations showed flow-rate dependence. At the lowest flow rate the Na concentrations averaged 24.6±3.9 mEq/l (n=25) which fell first to a minimum and then rose to a plateau of about 60 mEq/l as flow rate increased to a maximum. The excretory curve showed no tendency to approach the concentrations seen in primary saliva. The K excretory curve was typical of that seen in most other salivary glands, having high concentrations at low flow rates which fell towards a plateau above primary fluid levels as flow rate increased. The salivary bicarbonate concentration was always above that in plasma; it tended to rise to a plateau of about 48 mEq/l at the highest flow rates. This concentration is probably greater than that present in primary fluid although the primary levels have not been measured directly. The results are best interpreted in terms of a modified two-stage hypothesis. First a primary, Na-rich, K-poor secretion is formed in the acinar-intercalated duct region whose composition, although decidedly not plasma-like, is constant irrespective of the degree of gland stimulation. Then, secondarily, this fluid is modified during passage along the striated and excretory ducts by processes of Na reabsorption and K and HCO3 secretion. These secondary transport processes are not transport-maximum-limited but appear to increase with increasing degree of stimulation resulting in a phenomenon which could be termed acinar-tubular balance. Although it has not proven possible to micropuncture striated ducts in the rat submaxillary or parotid glands, in the sublingual gland we were able to do so in a few cases. For the first time we are able to offer direct proof that these ducts do contain hypotonic fluid.

Physiological and pharmacological regulation of human salivary electrolyte concentrations; with a discussion of electrolyte concentrations of some other exocrine secretions.

The electrolyte content of paraffin-stimulated, whole, mixed saliva obtained from patients with congestive heart failure is characterized by lower sodium, lower chloride, and higher potassium concentrations than saliva of normal subjects (1). Since these data suggested possible increased adrenal cortical activity in patients with heart failure, desoxycorticosterone acetate (DCA) was administered to nineteen normal subjects. It also seemed of interest to study additional pharmacological and physiological mechanisms that may play a role in the regulation of salivary electrolyte concentrations. Thus, the aims of this communication are to present: 1) Data on normal salivary concentrations of sodium, chloride, and potassium; 2) data relating to physiological mechanisms regulating the concentrations of salivary electrolytes; and 3) the effects on salivary electrolytes of three pharmacologic agents: desoxycorticosterone acetate (DCA), pilocarpine, and Mercuhydrin@.