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Funder JW, Pearce PT, Smith R, Smith AI. Mineralocorticoid action: target tissue specificity is enzyme, not receptor, mediated. Science 1988; 242:583-5. [PMID: 2845584 DOI: 10.1126/science.2845584] [Citation(s) in RCA: 1139] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mineralocorticoid receptors, both when in tissue extracts and when recombinant-derived, have equal affinity for the physiological mineralocorticoid aldosterone and for the glucocorticoids cortisol and corticosterone, which circulate at much higher concentrations than aldosterone. Such receptors are found in physiological mineralocorticoid target tissues (kidney, parotid, and colon) and in nontarget tissues such as hippocampus and heart. In mineralocorticoid target tissues the receptors are selective for aldosterone in vivo because of the presence of the enzyme 11 beta-hydroxy-steroid dehydrogenase, which converts cortisol and corticosterone, but not aldosterone, to their 11-keto analogs. These analogs cannot bind to mineralocorticoid receptors.
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Chao KS, Deasy JO, Markman J, Haynie J, Perez CA, Purdy JA, Low DA. A prospective study of salivary function sparing in patients with head-and-neck cancers receiving intensity-modulated or three-dimensional radiation therapy: initial results. Int J Radiat Oncol Biol Phys 2001; 49:907-16. [PMID: 11240231 DOI: 10.1016/s0360-3016(00)01441-3] [Citation(s) in RCA: 438] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES In a prospective clinical study, we tested the hypothesis that sparing the parotid glands may result in significant objective and subjective improvement of xerostomia in patients with head-and-neck cancers. The functional outcome 6 months after the completion of radiation therapy is presented. METHODS AND MATERIALS From February 1997 to February 1999, 41 patients with head-and-neck cancers were enrolled in a prospective salivary function study. Inverse-planning intensity-modulated radiation therapy (IMRT) was used to treat 27 patients, and forward-planning three-dimensional radiation therapy in 14. To avoid potential bias in data interpretation, only patients whose submandibular glands received greater than 50 Gy were eligible. Attempts were made to spare the superficial lobe of the parotid glands to avoid underdosing tumor targets in the parapharyngeal space; however, the entire parotid volume was used to compute dose-volume histograms (DVHs) for this analysis. DVHs were computed for each gland separately. Parotid function was assessed objectively by measuring stimulated and unstimulated saliva flow before and 6 months after the completion of radiation therapy. Measurements were converted to flow rate (mL/min) and normalized relative to that before treatment. The corresponding quality-of-life (QOL) outcome was assessed by five questions regarding the patient's oral discomfort and eating/speaking problems. RESULTS We observed a correlation between parotid mean dose and the fractional reduction of stimulated saliva output at 6 months after the completion of radiation therapy. We further examined whether the functional outcome could be modeled as a function of dose. Two models were found to describe the dose-response data well. The first model assumed that each parotid gland is comprised of multiple independent parallel functional subunits (corresponding to computed tomography voxels) and that each gland contributes equally to overall flow, and that saliva output decreases exponentially as a quadratic function of irradiation dose to each voxel. The second approach uses the equivalent uniform dose (EUD) metrics, which assumes loss of salivary function with increase in EUD for each parotid gland independently. The analysis suggested that the mean dose to each parotid gland is a reasonable indicator for the functional outcome of each gland. The corresponding exponential coefficient was 0.0428/Gy (95% confidence interval: 0.01, 0.09). The QOL questions on eating/speaking function were significantly correlated with stimulated and unstimulated saliva flow at 6 months. In a multivariate analysis, a toxicity score derived from the model based on radiation dose to the parotid gland was found to be the sole significant predictive factor for xerostomia. Neither radiation technique (IMRT vs. non-IMRT) nor chemotherapy (yes or no) independently influenced the functional outcome of the salivary glands. CONCLUSION Sparing of the parotid glands translates into objective and subjective improvement of both xerostomia and QOL scores in patients with head-and-neck cancers receiving radiation therapy. Modeling results suggest an exponential relationship between saliva flow reduction and mean parotid dose for each gland. We found that the stimulated saliva flow at 6 months after treatment is reduced exponentially, for each gland independently, at a rate of approximately 4% per Gy of mean parotid dose.
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Maruyama Y, Gallacher DV, Petersen OH. Voltage and Ca2+-activated K+ channel in baso-lateral acinar cell membranes of mammalian salivary glands. Nature 1983; 302:827-9. [PMID: 6302513 DOI: 10.1038/302827a0] [Citation(s) in RCA: 199] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nervous or hormonal stimulation of many exocrine glands evokes release of cellular K+ (ref. 1), as originally demonstrated in mammalian salivary glands2,3, and is associated with a marked increase in membrane conductance1,4,5. We now demonstrate directly, by using the patch-clamp technique6, the existence of a K+ channel with a large conductance localized in the baso-lateral plasma membranes of mouse and rat salivary gland acinar cells. The K+ channel has a conductance of approximately 250 pS in the presence of high K+ solutions on both sides of the membrane. Although mammalian exocrine glands are believed not to possess voltage-activated channels1,7, the probability of opening the salivary gland K+ channel was increased by membrane depolarization. The frequency of channel opening, particularly at higher membrane potentials, was increased markedly by elevating the internal ionized Ca2+ concentration, as previously shown for high-conductance K+ channels from cells of neural origin8-10. The Ca2+ and voltage-activated K+ channel explains the marked cellular K+ release that is characteristically observed when salivary glands are stimulated to secrete.
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Dawes C. The effects of flow rate and duration of stimulation on the condentrations of protein and the main electrolytes in human parotid saliva. Arch Oral Biol 1969; 14:277-94. [PMID: 5255441 DOI: 10.1016/0003-9969(69)90231-3] [Citation(s) in RCA: 187] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Blanco AI, Chao KSC, El Naqa I, Franklin GE, Zakarian K, Vicic M, Deasy JO. Dose-volume modeling of salivary function in patients with head-and-neck cancer receiving radiotherapy. Int J Radiat Oncol Biol Phys 2005; 62:1055-69. [PMID: 15990009 DOI: 10.1016/j.ijrobp.2004.12.076] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 12/07/2004] [Accepted: 12/16/2004] [Indexed: 01/20/2023]
Abstract
PURPOSE We investigated the factors that affect salivary function after head-and-neck radiotherapy (RT), including parotid gland dose-volume effects, potential compensation by less-irradiated gland tissue, and functional recovery over time. METHODS AND MATERIALS Sixty-five patients with head-and-neck tumors were enrolled in a prospective salivary function study. RT was delivered using intensity-modulated RT (n = 45), forward-planning three-dimensional conformal RT (n = 14), or three-dimensional conformal RT with an intensity-modulated RT boost (n = 6). Whole salivary flow was measured before therapy and at 6 months (n = 61) and 12 months (n = 31) after RT. A wide variety of dose-volume models to predict post-RT salivary function were tested. Xerostomia was defined according to the subjective, objective, management, analytic (SOMA) criteria as occurring when posttreatment salivary function was < 25% of the pretreatment function. Multivariate logistic regression analysis was used to assess the combined effect of dose-volume, patient-, and treatment-related factors. RESULTS A significant correlation was observed between the relative quality-of-life scores and relative stimulated saliva values at 6 months after RT (Spearman's correlation coefficient [R(s)] = 0.46, p < 0.001). The dose-volume factors were by far the strongest correlates with stimulated saliva flow, although other factors showed modest significance in multimetric models (chemotherapy, gender, and Karnofsky performance status). Several fitted dose-volume models provided a good mathematical description of the data. Significant noise in the salivary measurements (repeated measurement coefficient of variation was 27% in normal subjects) precluded selection of any one of the models presented solely on the basis of the objective fit criteria. Nevertheless, the mean dose-exponential model, in which each parotid gland's relative salivary gland function equaled exp(-A x mean gland dose), with A equal to 0.054/Gy (68% confidence interval 0.052-0.059), provided a good representation of the data and was incorporated into our multimetric analysis. Using that model, we estimated that a mean parotid dose of 25.8 Gy, on average, was likely to reduce a single parotid gland's flow to 25% of its pretreatment value, regardless of the treatment delivery method. Significant correlations were observed between a logistic multivariate model (incorporating the mean dose-exponential equation, gender, and Karnofsky performance status) and stimulated saliva flow at 6 months (R(s) = 0.73), stimulated saliva flow at 12 months (R(s) = 0.54), and quality-of-life score at 6 months (R(s) = 0.35) after RT. CONCLUSION Stimulated parotid salivary gland dose-volume models strongly correlated with both stimulated salivary function and quality-of-life scores at 6 months after RT. The mean stimulated saliva flow rates improved from 6 to 12 months after RT. Salivary function, in each gland, appeared to be lost exponentially at a rate of approximately 5%/1 Gy of mean dose. Additional research is necessary to distinguish among the models for use in treatment planning. The incidence of xerostomia was significantly decreased when the mean dose of at least one parotid gland was kept to < 25.8 Gy with conventional fractionation. However, even lower mean doses imply increased late salivary function.
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Research Support, U.S. Gov't, P.H.S. |
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Kwong DLW, Pow EHN, Sham JST, McMillan AS, Leung LHT, Leung WK, Chua DTT, Cheng ACK, Wu PM, Au GKH. Intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma: a prospective study on disease control and preservation of salivary function. Cancer 2004; 101:1584-93. [PMID: 15378492 DOI: 10.1002/cncr.20552] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively. METHODS Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT. RESULTS At a median follow-up of 2 years, only 1 neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at 1 year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time. CONCLUSIONS Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC.
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Arreola J, Melvin JE, Begenisich T. Activation of calcium-dependent chloride channels in rat parotid acinar cells. J Gen Physiol 1996; 108:35-47. [PMID: 8817383 PMCID: PMC2229297 DOI: 10.1085/jgp.108.1.35] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Ca2+ and voltage dependence of Ca(2+)-activated Cl- currents in rat parotid acinar cells was examined with the whole-cell patch clamp technique. Acinar cells were dialyzed with buffered free Ca2+ concentrations ([Ca2+]i) from < 1 nM to 5 microM. Increasing [Ca2+]i induced an increase in Cl- current at all membrane potentials. In cells dialyzed with [Ca2+]i > 25 nM, depolarizing test pulses activated a Cl- current that was composed of an instantaneous and a slow monoexponential component. The steady-state current-voltage relationship showed outward rectification at low [Ca2+]i but became more linear as the [Ca2+]i increased because of a shift in Cl- channel activation toward more negative voltages. The Ca2+ dependence of steady-state channel activation at various membrane voltages was fit by the Hill equation. The apparent Kd and Hill coefficient obtained from this analysis were both functions of membrane potential. The Kd decreased from 417 to 63 nM between -106 and +94 mV, whereas the Hill coefficient was always > 1 and increased to values as large as 2.5 at large positive potentials. We found that a relatively simple mechanistic model can account for the channel steady-state and kinetic behavior. In this model, channel activation involves two identical, independent, sequential Ca2+ binding steps before a final Ca(2+)-independent transition to the conducting conformation. Channel activation proceeds sequentially through three closed states before reaching the open state. The Ca2+ binding steps of this model have a voltage dependence similar to that of the Kd from the Hill analysis. The simplest interpretation of our findings is that these channels are directly activated by Ca2+ ions that bind to sites approximately 13% into the membrane electric field from the cytoplasmic surface.
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Inoue H, Ono K, Masuda W, Morimoto Y, Tanaka T, Yokota M, Inenaga K. Gender difference in unstimulated whole saliva flow rate and salivary gland sizes. Arch Oral Biol 2006; 51:1055-60. [PMID: 16919593 DOI: 10.1016/j.archoralbio.2006.06.010] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 06/14/2006] [Accepted: 06/20/2006] [Indexed: 11/22/2022]
Abstract
OBJECTIVE A gender difference in the unstimulated whole saliva flow rate (UWSFR) may be due to a difference in the sizes of the salivary glands. In this study, we investigated the relationships among the UWSFR, gland sizes and body sizes of healthy young adult males and females. DESIGN Unstimulated whole saliva was collected for 5 min by the spitting method in 50 healthy young adults, and the flow rate of the saliva was measured. Heights and weights were measured, and body mass indices (BMI) were calculated. The sizes of the salivary glands were measured by use of a magnetic resonance imaging technique. RESULTS Parotid and submandibular gland sizes and flow rates in females were significantly smaller than those in males, as were also the weights, heights and BMI. In both males and females, there were significant positive correlations between gland sizes and the flow rates, weights and BMI. The variations of the flow rates were reduced by standardizing them with gland sizes, weights and BMI. CONCLUSIONS These results suggest that the lower UWSFR in females as compared with males is due to the smaller gland sizes due to the smaller body sizes.
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Leslie BA, Putney JW, Sherman JM. alpha-Adrenergic, beta-adrenergic and cholinergic mechanisms for amylase secretion by rat parotid gland in vitro. J Physiol 1976; 260:351-70. [PMID: 185365 PMCID: PMC1309095 DOI: 10.1113/jphysiol.1976.sp011519] [Citation(s) in RCA: 117] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
1. Rat parotid gland slices, incubated in a balanced, buffered salt solution, were found to be physiologically stable for up to 2 hr with respect to O2 consumption, water content, extracellular space and cation content. 2. The slices could be stimulated to secrete amylase by activation of alpha-adrenergic, beta-adrenergic or muscarinic cholinergic receptors. 3. The secretion elicited through all three receptors appeared to involve exocytosis as revealed by electron microscopy. 4. The beta-agonist, isoprenaline, increased tissue content of cyclic adenosine 3',5'-monophosphate (cyclic AMP); alpha-adrenergic and cholinergic agents had no effect on the level of this cyclic nucleotide. 5. Secretion via cholinergic or alpha-adrenergic mechanisms required extra-cellular calcium; the beta-adrenergic mechanism did not. 6. It was concluded that stimulation of rat parotid cells activates distinctly separate pathways leading ultimately to exocytosis, one pathway involving cyclic AMP, and the other, external Ca2+ ion.
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Foskett JK. [Ca2+]i modulation of Cl- content controls cell volume in single salivary acinar cells during fluid secretion. THE AMERICAN JOURNAL OF PHYSIOLOGY 1990; 259:C998-1004. [PMID: 2260645 DOI: 10.1152/ajpcell.1990.259.6.c998] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Differential interference contrast microscopy and low-light-level digital imaging of the fluorescent chloride indicator dye 6-methyl-1-(3-sulfonatopropyl)quinolinium (SPQ) were performed simultaneously in single mammalian salivary gland acinar cells to examine the relationship between cytoplasmic chloride concentration [( Cl-]i) and cell volume during stimulus-secretion coupling. Agonist stimulation of Cl(-)-driven fluid secretion is associated with rapid, Ca2(+)-dependent changes of cell volume, which are temporally coupled to changes of [Cl-]i. The agonist-induced changes in [Cl-]i, if accompanied by cations and water, quantitatively account for the cell volume changes, demonstrating in a single cell that cell volume is determined by cell solute content. Agonist-induced modulation of cell volume appears to be a consequence of the requirement to develop appropriate ion gradients necessary for vectorial salt (and fluid) transport.
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Riedel D, Antonin W, Fernandez-Chacon R, Alvarez de Toledo G, Jo T, Geppert M, Valentijn JA, Valentijn K, Jamieson JD, Südhof TC, Jahn R. Rab3D is not required for exocrine exocytosis but for maintenance of normally sized secretory granules. Mol Cell Biol 2002; 22:6487-97. [PMID: 12192047 PMCID: PMC135623 DOI: 10.1128/mcb.22.18.6487-6497.2002] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rab3D, a member of the Rab3 subfamily of the Rab/ypt GTPases, is expressed on zymogen granules in the pancreas as well as on secretory vesicles in mast cells and in the parotid gland. To shed light on the function of Rab3D, we have generated Rab3D-deficient mice. These mice are viable and have no obvious phenotypic changes. Secretion of mast cells is normal as revealed by capacitance patch clamping. Furthermore, enzyme content and overall morphology are unchanged in pancreatic and parotid acinar cells of knockout mice. Both the exocrine pancreas and the parotid gland show normal release kinetics in response to secretagogue stimulation, suggesting that Rab3D is not involved in exocytosis. However, the size of secretory granules in both the exocrine pancreas and the parotid gland is significantly increased, with the volume being doubled. We conclude that Rab3D exerts its function during granule maturation, possibly by preventing homotypic fusion of secretory granules.
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Stetler G, Brewer MT, Thompson RC. Isolation and sequence of a human gene encoding a potent inhibitor of leukocyte proteases. Nucleic Acids Res 1986; 14:7883-96. [PMID: 3640338 PMCID: PMC311822 DOI: 10.1093/nar/14.20.7883] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We report the isolation of the human gene encoding an inhibitor of neutrophil elastase and cathepsin G. We have sequenced the gene and a cDNA clone isolated from human parotid tissue. The protein encoded by this gene appears to contain two functional domains, one having a trypsin inhibitory site and the other an elastase inhibitory site. The two-domain structure of the protein is reflected in the organization of the gene, with each domain represented by a separate exon. We have also noted that the intervening sequence separating the trypsin-inhibitor-exon and the elastase-inhibitor-exon is flanked by eleven base-pair direct repeats, suggesting that this intron may have been generated by a transposition-type event.
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DENTON DA. The study of sheep with permanent unilateral parotid fistulae. QUARTERLY JOURNAL OF EXPERIMENTAL PHYSIOLOGY AND COGNATE MEDICAL SCIENCES 1957; 42:72-95. [PMID: 13485358 DOI: 10.1113/expphysiol.1957.sp001244] [Citation(s) in RCA: 106] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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SHANNON IL, PRIGMORE JR, CHAUNCEY HH. Modified Carlson-Crittenden Device for the Collection of Parotid Fluid. J Dent Res 2016; 41:778-83. [PMID: 13911246 DOI: 10.1177/00220345620410040801] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Ishikawa Y, Yuan Z, Inoue N, Skowronski MT, Nakae Y, Shono M, Cho G, Yasui M, Agre P, Nielsen S. Identification of AQP5 in lipid rafts and its translocation to apical membranes by activation of M3 mAChRs in interlobular ducts of rat parotid gland. Am J Physiol Cell Physiol 2005; 289:C1303-11. [PMID: 16107506 DOI: 10.1152/ajpcell.00211.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aquaporin-5 (AQP5), an apical plasma membrane (APM) water channel in salivary glands, lacrimal glands, and airway epithelium, has an important role in fluid secretion. M(3) muscarinic acetylcholine receptor (mAChR)-induced changes in AQP5 localization in rat parotid glands were investigated with immunofluorescence or immunoelectron microscopy, detergent solubility, and gradient density floatation assays. Confocal microscopy revealed AQP5 localization in intracellular vesicles of interlobular duct cells in rat parotid glands and AQP5 trafficking to the APM 10 min after injection of the mAChR agonist cevimeline. Conversely, 60 min after injection, there was a diffuse pattern of AQP5 staining in the cell cytoplasm. The calcium ionophore A-23187 mimicked the effects of cevimeline. Immunoelectron microscopic studies confirmed that cevimeline induced AQP5 trafficking from intracellular structures to APMs in the interlobular duct cells of rat parotid glands. Lipid raft markers flotillin-2 and GM1 colocalized with AQP5 and moved with AQP5 in response to cevimeline. Under control conditions, the majority of AQP5 localized in the Triton X-100-insoluble fraction and floated to the light-density fraction on discontinuous density gradients. After 10-min incubation of parotid tissue slices with cevimeline or A-23187, AQP5 levels decreased in the Triton X-100-insoluble fraction and increased in the Triton X-100-soluble fraction. Thus AQP5 localizes in the intracellular lipid rafts, and M(3) mAChR activation induces AQP5 trafficking to the APM with lipid rafts via intracellular Ca(2+) signaling and induces AQP5 dissociation from lipid rafts to nonrafts on the APM in the interlobular duct cells of rat parotid glands.
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Research Support, Non-U.S. Gov't |
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Brandtzaeg P, Fjellanger I, Gjeruldsen ST. Immunoglobulin M: local synthesis and selective secretion in patients with immunoglobulin A deficiency. Science 1968; 160:789-91. [PMID: 4171541 DOI: 10.1126/science.160.3829.789] [Citation(s) in RCA: 102] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Local synthesis seems to be decisive for the selective secretion of 19S immunoglobulin M into parotid secretions. The "transport piece" is apparently not involved in the secretion of immunoglobulin M, for there is no association between the two components. The possible significance of the normal association of transport piece with secreted immunoglobulin A remains to be clarified.
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De Camilli P, Peluchetti D, Meldolesi J. Dynamic changes of the luminal plasmalemma in stimulated parotid acinar cells. A freeze-fracture study. J Cell Biol 1976; 70:59-74. [PMID: 932102 PMCID: PMC2109805 DOI: 10.1083/jcb.70.1.59] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In the acinar cells of the rat parotid gland the two membranes participating in exocytosis, i.e., the luminal plasmalemma and the secretory granule membrane, are clearly distinguishable in freeze-fracture because of their different densities in particles. In order to obtain point-specific information about the fusion-fission of these two membranes that occurs during the secretory cycle, glands were studied at various times (5 min to 6 h) after stimulation with isoproterenol. We observed that, in the course of the release of secretion products and shortly afterwards, the enlarged luminal plasmalemma exhibits a mosaic organization consisting of an alternation of membrane patches of high (original plasmalemma) and low (fused granule membrane) particle density. The transition between these two patterns is usually sharp. Later, concomitant with the reformation of acinar canaliculi, the low particle density membrane is found at the cell surface but only bounding vacuolar infoldings, and then it finally disappears. These results suggest that (a) fusion of these membranes does not result in a random intermixing of the molecular components of the participating membranes, which retain their structural identity; and (b) the enlarged luminal plasmalemma reverts to its original size by a progressive, specific removal of the regions of low particle density from the cell surface.
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Abstract
This article discusses the anatomy, physiology, and pathology of the parotid, submandibular, and sublingual glands, which often are referred to as the major salivary glands. Overall, diseases of the salivary glands are relatively uncommon; however, as an organ system, they have the greatest diversity of pathology. Acute viral and bacterial inflammatory diseases are the most common salivary gland abnormalities; tumors are uncommon. The imaging approach to these lesions is discussed.
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Review |
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O'Sullivan JM, Jenkinson HF, Cannon RD. Adhesion of Candida albicans to oral streptococci is promoted by selective adsorption of salivary proteins to the streptococcal cell surface. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 1):41-48. [PMID: 10658650 DOI: 10.1099/00221287-146-1-41] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Adhesion of Candida albicans to saliva-coated surfaces is an important early step in the colonization of the oral cavity. C. albicans cells also adhere to several species of oral streptococci including Streptococcus gordonii, Streptococcus oralis and Streptococcus sanguinis in what are believed to be multi-modal interactions. It is now demonstrated that incubation of streptococcal cells of these species with human parotid saliva further promotes the adhesion of C. albicans cells by up to 2-3-fold. Various species of streptococci were shown to adsorb different protein components of parotid saliva to their cell surfaces. The basic proline-rich proteins (bPRPs), to which C. albicans cells bind on nitrocellulose blot overlay, were strongly adsorbed to the surface of S. gordonii cells but not to S. oralis cells. Parotid saliva that was pre-adsorbed with S. gordonii cells and then applied to hydroxylapatite beads was <50% effective at supporting adhesion of C. albicans compared with control (non-adsorbed) saliva, demonstrating that bPRPs are major pellicle receptors. C. albicans cells did not adsorb bPRPs from fluid-phase parotid saliva. Following size-exclusion chromatography of parotid saliva samples, pooled fractions enriched in bPRPs promoted maximal adhesion of C. albicans to S. gordonii cells. The results demonstrate that C. albicans cells recognize only surface-bound forms of bPRPs and suggest that these proteins adsorbed to enamel or to streptococcal surfaces promote C. albicans adhesion and oral colonization.
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Bussels B, Maes A, Flamen P, Lambin P, Erven K, Hermans R, Nuyts S, Weltens C, Cecere S, Lesaffre E, Van den Bogaert W. Dose-response relationships within the parotid gland after radiotherapy for head and neck cancer. Radiother Oncol 2005; 73:297-306. [PMID: 15588874 DOI: 10.1016/j.radonc.2004.09.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 09/01/2004] [Accepted: 09/09/2004] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE To determine the salivary function, after parotid-sparing radiotherapy (RT), of different regions within the parotid gland and to evaluate dose-function relationships within the parotid glands and between patients. PATIENTS AND METHODS Sixteen head and neck cancer patients, irradiated between September 1999 and November 2000 using a conformal parotid-sparing technique, were included in this study. Before RT and 7 months after RT (range 6-10 months), a salivary gland scintigraphy was performed in all patients combined with a single photon emission computed tomography (SPECT). The salivary excretion fraction (SEF) was measured, after stimulation, in 8-12 transverse 5mm SPECT slices of each parotid. Loss of salivary excretion fraction (dSEF %) of these slices was calculated as the proportion of SEF after RT as compared to SEF before RT. Since the planning CT-scan and the SPECT-scintigraphy were performed in the same treatment position, the dose to a transverse slice within the parotid gland could be matched to the loss of salivary excretion fraction of that respective slice. A non-linear model was fitted to the dose-loss of function data and the dose resulting in 50% loss of salivary excretion fraction (D50) was calculated. RESULTS Before RT, all but one patient presented with normal salivary excretion fractions (SEF) of both parotid glands. Within the same parotid gland, the SEF's of the different slices were almost equal. Seven months after RT, the reduction in SEF was statistically significant (P-value<0.0001). A significant difference in loss of salivary excretion fraction (dSEF) was also observed between both parotid glands (P<0.0001) as a result of the parotid-sparing technique. When plotting the dSEF of a slice versus the dose given to that slice, doses as low as 10-15 Gy could result in a serious loss of function (dSEF>50%). After fitting a non-linear model to these plots, the mean dose resulting in 50% loss of salivary excretion fraction (D50) 7 months after RT was 22.5 Gy. A large inter-patient variability was found in D50. CONCLUSIONS Salivary SPECT is a useful tool for the evaluation of the salivary function of different slices within the parotid gland. Before irradiation, the different slices within one parotid gland act as functional sub-units contributing equally to the function of the entire gland. Seven months after an average dose of 22.5 Gy (D50) the functional sub-unit has lost 50% of its excretion fraction. The high inter-patient variability in D50 and the observation that low doses (10-15 Gy) can induce serious loss of function should prompt us in the clinic to reduce the dose to the parotids even lower than the threshold of 22.5 Gy.
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Soltoff SP, McMillian MK, Talamo BR. ATP activates a cation-permeable pathway in rat parotid acinar cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1992; 262:C934-40. [PMID: 1566819 DOI: 10.1152/ajpcell.1992.262.4.c934] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Effects of several purinergic receptor agonists were examined on rat parotid acinar cells. Extracellular ATP stimulated 45Ca2+ uptake into isolated rat parotid acinar cells in a concentration-dependent fashion (EC50 approximately 125 microM ATP) at a maximum rate of approximately 6 nmol.mg protein-1.min-1. In the absence of extracellular Na+, ATP increased the uptake rate by greater than 100%. Increasing concentrations of extracellular Na+ reduced the ATP-stimulated rate of 45Ca2+ entry in a graded fashion (IC50 16.6 mM), suggesting that Ca2+ and Na+ compete for entry. Uptake rate was not reduced when intracellular Ca2+ was buffered with 1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid, indicating that the effects of ATP were not initiated by an elevation in intracellular free Ca2+ concentration. 3-O-(4'-benzoyl)benzoyl-ATP was much more potent (EC50 approximately 4 microM) and stimulated Ca2+ influx at a greater rate (approximately 12 nmol.mg protein-1.min-1) than ATP. Other nucleotide analogues, including adenosine 5'-O-(3-thiotriphosphate), 2-methylthio-ATP, and 5'-adenylylimidodiphosphate, were much less effective than ATP. ATP produced a biphasic effect on membrane potential: an initial hyperpolarization was followed by a rapid depolarization. The depolarization was greatly reduced in the absence of extracellular Na+, but not in the absence of extracellular Ca2+, indicating that the majority of the depolarizing current was due to Na+ entry. Effects of ATP on the membrane potential were distinguishable from those of the Ca2+ ionophore ionomycin and the muscarinic agonist carbachol. Depolarization of the cells by gramicidin or K+ did not produce an increase in 45Ca2+ uptake.(ABSTRACT TRUNCATED AT 250 WORDS)
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