Secretion of saliva by the rabbit mandibular gland in vitro : the role of anions

1981 ◽  
Vol 296 (1080) ◽  
pp. 179-192 ◽  
Keyword(s):  
Mandibular Gland ◽  
Fluid Secretion ◽  
Salivary Secretion ◽  
Suitable Alternative ◽  
Secretory Rate ◽  
Complete Replacement ◽  
Primary Fluid ◽  
Gland Duct

Salivary glands form their secretions by first elaborating an isotonic plasma-like primary fluid in the endpieces and then modifying the composition of this secretion during its passage along the gland duct system. We have studied the role of extracellular anions in both primary secretion and ductal modification with a recently developed technique for isolation and perfusion of the rabbit mandibular gland. Neither of the major extracellular anions (Cl - or HCO - 3 ) is essential for primary fluid secretion. HCO - 3 can be removed altogether and replaced with Cl - without diminution in secretory rate, provided that extracellular pH is maintained at 7.4, and its replacement with acetate actually enhances secretion. Complete replacement of Cl - with Br - also enhances secretion and replacement with I - , NO - 3 , CH 3 SO 4 or isethionate supports secretion but at progressively diminishing rates. Our data do not yet allow us to distinguish between an electroneutral Na + -Cl - cotransport model or a double countertransport (Na + -H + plus Cl - -HCO - 3 ) model as the basis of primary salivary secretion, or to propose any more suitable alternative model. With respect to ductal modification of the primary saliva, HCO - 3 omission inhibits ductal Na + absorption (i.e. salivary Na + concentration rises). This inhibition is probably related to an effect of pH on the postulated Na + -H + exchange mechanism in the luminal duct membrane since it can also be induced by lowering perfusate pH, and reversed by substitution of perfusate HCO - 3 with acetate (which enters saliva) but not HEPES (which does not enter the saliva). Substitution of perfusate Cl - with other anions seems not to inhibit ductal Na+ and K + transport markedly.

Effects of secretagogues on cytosolic Ca2+ levels in rat submandibular granular ducts and acini

1991 ◽  
Vol 261 (2) ◽  
pp. G359-G363 ◽  
Author(s):  
I. H. Valdez ◽  
R. J. Turner
Keyword(s):  
Substance P ◽  
Salivary Secretion ◽  
Male Rat ◽  
Primary Fluid ◽  
Epidermal Growth ◽  
Submandibular Acini ◽  
Stage Process ◽  
Granular Ducts ◽  
Substance P Receptors

Saliva is thought to be formed by a two-stage process, with the secretion of a "primary fluid" by the acinar cells followed by various ionic modifications in the salivary ducts. Both of these processes are under the control of autonomic stimuli. Although the role of the acini in salivary secretion has been studied in some detail, little is known about properties of ducts, particularly the intralobular ducts that make up the bulk of the ductal tissue. In the present study, microfluorometric methods were employed to examine the responses of intracellular Ca2+ concentration ([Ca2+]i) in individual male rat submandibular acini and intralobular (granular) ducts to various fluid secretory stimuli. We show that granular ducts respond to muscarinic (carbachol) and alpha-adrenergic (epinephrine) stimulation by increasing [Ca2+]i in a manner that is qualitatively similar to acini, but that in contrast to acini, these ducts do not respond to substance P. Because the transduction of a substance P peptidergic signal typically occurs via increased [Ca2+]i, this observation suggests that there are no substance P receptors on granular ducts. Ducts were also found to be somewhat more responsive to both carbachol and epinephrine than acini. Although muscarinic, alpha-adrenergic, and vasoactive intestinal peptide (VIP) stimulation are known to induce the secretion of epidermal growth factor from granular ducts, no significant increase in ductal [Ca2+]i in response to VIP (10(-9) to 10(-6) M) was observed.

Role of calcium in cholinergic and adrenergic mechanisms of eccrine sweat secretion

1981 ◽  
Vol 241 (3) ◽  
pp. C113-C120 ◽  
Author(s):  
K. Sato ◽  
F. Sato
Keyword(s):  
Sweat Rate ◽  
Sweat Glands ◽  
Hyperbolic Function ◽  
Ionophore A23187 ◽  
Secretory Rate ◽  
Sweat Secretion ◽  
Eccrine Sweat Glands ◽  
Eccrine Sweat

The role of Ca2+ in eccrine sweat secretion was studied using isolated cannulated monkey palm eccrine sweat glands in vitro. Removal of Ca2+ from the incubation medium promptly abolished sweat secretion induced by methacholine or phenylephrine. In contrast, isoproterenol-induced sweat secretion lasted from 40 to 220 min in a Ca2+-free medium. The methacholine-induced maximal sweat rate was a hyperbolic function of the Ca2+ concentration in the bath and reached a plateau at 1 mM Ca2+. Higher Ca2+ concentrations rather suppressed the secretory rate. The Ca2+ ionophore A23187, but not X537A, at 3 X 10(-6) M induced copious prolonged sweat secretion after a latent period of 10 min. A23187-induced sweat secretion was not inhibited by either atropine or propranolol. D 600 (methoxyverapamil) at 10(-3) M inhibited sweat secretion induced by methacholine or by isoproterenol, although the latter lasted longer than methacholine sweating (20 vs. 5 min) in the presence of D 600. The data support the notion that Ca2+ influx into the cell plays a crucial role in cholinergic and alpha-adrenergic sweating, whereas a partial supply of Ca2+ for isoproterenol-induced sweating is derived from an intracellular store.

Decrease in rat submandibular acinar cell volume during ACh stimulation

1990 ◽  
Vol 258 (6) ◽  
pp. G878-G886 ◽  
Author(s):  
T. Nakahari ◽  
M. Murakami ◽  
H. Yoshida ◽  
M. Miyamoto ◽  
Y. Sohma ◽  
...  
Keyword(s):  
Cell Volume ◽  
Acinar Cell ◽  
Basolateral Membrane ◽  
Fluid Secretion ◽  
Salivary Secretion ◽  
Impedance Method ◽  
Fluid Flux ◽  
Secretory Rate ◽  
Morphometric Method ◽  
Volume Decrease

Changes in acinar cell volume were measured in the perfused submandibular gland of the rat at 23 degrees C during salivary secretion induced by acetylcholine (ACh). Cellular volume was monitored by two methods: the impedance method and the morphometric method using video-enhanced contrast optical microscopy. Both measurements revealed a decrease in acinar cell volume in response to 1 microM ACh. Within the 1st min of stimulation, secretion increased to the initial maximum (initial secretion), and cell shrinkage occurred. During sustained stimulation, secretory rate and cell volume were maintained at the plateau level (steady secretion). The decrease in cell volume was 71.8 +/- 2.9% of resting volume (means +/- SE, n = 8) as measured by the impedance method and 76.1 +/- 2.0% (n = 20) as measured by the morphometric method. With the removal of ACh, cell volume increased to 111.6 +/- 2.7% (n = 8) of the prestimulation level as measured by the impedance method and 108.8 +/- 1.5% (n = 20) as measured by the morphometric method, and then recovered to the prestimulation level slowly. The weight of the gland decreased significantly during stimulation. These findings proved that volume decrease occurred during stimulation. The measurement of cell volume gave the net fluid flux of the acinar cell compartment. The net fluid flux and the rate of salivary secretion gave an estimation of the fluid influx across the basolateral membrane. These findings suggest that a transcellular route for fluid secretion exists in the salivary gland.

Effects of Ion Transport Inhibition on Rat Mandibular Gland Secretion

1987 ◽  
Vol 66 (2) ◽  
pp. 531-536 ◽  
Author(s):  
J.A. Young ◽  
D.I. Cook ◽  
L.A.R. Evans ◽  
D. Pirani
Keyword(s):  
Ion Transport ◽  
Plasma Membranes ◽  
Mandibular Gland ◽  
Secretory Cells ◽  
Anion Channels ◽  
Secretory Rate ◽  
Ca Antagonist ◽  
Small Rise ◽  
Cytosol Ph

The effects of substituting gluconate for extracellular Cl, and of treatment with various ion transport blockers, on cytosol pH (pHi) and secretion by the acetylcholine stimulated rat mandibular gland were studied in vitro. Gluconate replacement increased pHi from 7.12 ± 0.02 to 7.27 ± 0.04, caused secretory rate to fall by 75%, and increased salivary HC03 from 14 ± 0.9 mmollL to 67 ± 1.5 mmoll L. Furosemide (I mmol/L), which blocks Na-K-2Cl symports and Cl-HCO 3 antiports, had effects similar to those of gluconate replacement, except that secretion was reduced only by 59%. Bumetanide (1 mmoll L), which blocks only Na-K-2Cl symports, caused a 67% reduction in secretion rate, but it had little effect on pHi and caused only a small rise in salivary HCO3 concentration. SITS (1 mmol/L), which blocks Cl-HCO3 antiports, increased pHi to 7.26 ± 0.03 and induced a small rise in the secretory rate. Methazolamide and acetazolamide (1 mmol/L), both of which inhibit carbonic anhydrase and may also block anion channels, increased pHi to 7.43 ± 0.02 and 7.20 ± 0.03, respectively, but had no effect on secretory rate, and reduced salivary HC03 slightly. Ba (3 mmol/L), tetraethylammonium (10 mmoll L), and decamethonium (5 mmol/L) all caused marked but reversible reductions in secretory rate, consistent with the known actions of these agents on K channels. Ba, however, also appeared to act as a Ca antagonist, an action that it seemed to share with Mn ions (5 mmoll L). The results are interpreted in terms of a secretion model based on the presence, in the baso-lateral plasma membranes of the secretory cells, not only of a Na-K-2Cl symport, but also of Na-H and Cl-HC03 antiports, contributing, respectively, to secretion in the proportions 8:5:3.

scholarly journals The characteristics of intracellular Ca2+ signals in vivo necessitate a new model for salivary fluid secretion

2021 ◽  
Author(s):  
Takahiro Takano ◽  
Amanda M. Wahl ◽  
Kai-Ting Huang ◽  
John Rugis ◽  
James Sneyd ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Fluid Secretion ◽  
Salivary Secretion ◽  
Apical Region ◽  
Isolated Cells ◽  
Marked Contrast ◽  
K Channels ◽  
Stimulation Of

AbstractSalivary fluid secretion involves an intricate choreography to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are based on experimental observations in enzymatically isolated cells where the Ca2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels. We monitored Ca2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca2+ transients that failed to propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. Given this incompatibility to the previous model, a new mathematical model was constructed to explain how salivary secretion can be efficiently stimulated by apically localized Ca2+ signals.

scholarly journals Highly Localized intracellular Ca2+ signals promote optimal salivary gland fluid secretion

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Takahiro Takano ◽  
Amanda Wahl ◽  
Kai-Ting Huang ◽  
Takanori Narita ◽  
John Rugis ◽  
...  
Keyword(s):  
Fluid Secretion ◽  
Salivary Secretion ◽  
Membrane Transporters ◽  
Apical Region ◽  
Isolated Cells ◽  
Marked Contrast ◽  
K Channels ◽  
Basolateral Plasma Membrane ◽  
Stimulation Of

Salivary fluid secretion involves an intricate choreography of membrane transporters to result in the trans-epithelial movement of NaCl and water into the acinus lumen. Current models are largely based on experimental observations in enzymatically isolated cells where the Ca2+ signal invariably propagates globally and thus appears ideally suited to activate spatially separated Cl and K channels, present on the apical and basolateral plasma membrane, respectively. We monitored Ca2+ signals and salivary secretion in live mice expressing GCamp6F, following stimulation of the nerves innervating the submandibular gland. Consistent with in vitro studies, Ca2+ signals were initiated in the apical endoplasmic reticulum. In marked contrast to in vitro data, highly localized trains of Ca2+ transients that failed to fully propagate from the apical region were observed. Following stimuli optimum for secretion, large apical-basal gradients were elicited. A new mathematical model, incorporating these data was constructed to probe how salivary secretion can be optimally stimulated by apical Ca2+ signals.

scholarly journals Role of Ajwa Date Fruit Pulp and Seed in the Management of Diseases through In Vitro and In Silico Analysis

Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 78
Author(s):  
Shehwaz Anwar ◽  
Ravindra Raut ◽  
Mohammed A. Alsahli ◽  
Ahmad Almatroudi ◽  
Hani Alfheeaid ◽  
...  
Keyword(s):  
Alternative Therapy ◽  
In Silico Analysis ◽  
Fruit Pulp ◽  
Aggregation Index ◽  
Suitable Alternative ◽  
Methanolic Extracts ◽  
Health Promoting ◽  
Seed Extracts

This study investigated the health-promoting activities of methanolic extracts of Ajwa date seed and fruit pulp extracts through in vitro studies. These studies confirmed potential antioxidant, anti-hemolytic, anti-proteolytic, and anti-bacterial activities associated with Ajwa dates. The EC50 values of fruit pulp and seed extracts in methanol were reported to be 1580.35 ± 0.37 and 1272.68 ± 0.27 µg/mL, respectively, in the DPPH test. The maximum percentage of hydrogen peroxide-reducing activity was 71.3 and 65.38% for both extracts at 600 µg/mL. Fruit pulp and seed extracts inhibited heat-induced BSA denaturation by 68.11 and 60.308%, heat-induced hemolysis by 63.84% and 58.10%, and hypersalinity-induced hemolysis by 61.71% and 57.27%, and showed the maximum anti-proteinase potential of 56.8 and 51.31% at 600 μg/mL, respectively. Seed and fruit pulp inhibited heat-induced egg albumin denaturation at the same concentration by 44.31 and 50.84%, respectively. Ajwa seed showed minimum browning intensity by 63.2%, percent aggregation index by 64.2%, and amyloid structure by 63.8% at 600 μg/mL. At 100 mg/mL, Ajwa seed extract exhibited good antibacterial activity. Molecular docking analysis showed that ten active constituents of Ajwa seeds bind with the critical antioxidant enzymes, catalase (1DGH) and superoxide dismutase (5YTU). The functional residues involved in such interactions include Arg72, Ala357, and Leu144 in 1DGH, and Gly37, Pro13, and Asp11 in 5YTU. Hence, Ajwa dates can be used to develop a suitable alternative therapy in various diseases, including diabetes and possibly COVID-19-associated complications.

Apparent Synthesis of Submaxillary Gland Amylase During Pilocarpine Administration

1956 ◽  
Vol 187 (2) ◽  
pp. 403-406 ◽  
Author(s):  
Leon H. Schneyer ◽  
Charlotte A. Schneyer
Keyword(s):  
Subcutaneous Administration ◽  
Submaxillary Gland ◽  
Fluid Secretion ◽  
Salivary Secretion ◽  
Secretory Proteins ◽  
Parotid Glands ◽  
Short Term ◽  
Secretory Rate ◽  
Appreciable Increase ◽  
Expected Increase

Administration of the parasympathomimetic drug pilocarpine has generally been observed to result in an increased rate of salivary secretion accompanied by depletion of gland stores of specific secretory proteins. In the experiments reported here, the expected increase in secretory rate and depletion of amylase stores were observed for the parotid glands of the rat after subcutaneous administration of pilocarpine. In the case of the sub-maxillary glands, short-term stimulation by pilocarpine, although observed to result in the expected increase in the rate of fluid secretion, led to no detectable depletion but to a rapid and appreciable increase in gland levels of amylase activity. Although the mechanism of this effect remains to be established, it appears possible that in this system stimulation by the parasympathomimetic agent pilocarpine results in an unmasking of a direct effect of stimulation on the process of synthesis of new enzyme.

Contribution of the Na+-K+-2Cl−cotransporter NKCC1 to Cl− secretion in rat OMCD

2001 ◽  
Vol 280 (5) ◽  
pp. F913-F921 ◽  
Author(s):  
Susan M. Wall ◽  
Michael P. Fischer ◽  
Pramod Mehta ◽  
Kathryn A. Hassell ◽  
Stanley J. Park
Keyword(s):  
Apical Membrane ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Basolateral Membrane ◽  
Physiological Role ◽  
Fluid Secretion ◽  
Transepithelial Potential ◽  
In Series

In rat kidney the “secretory” isoform of the Na+-K+-2Cl− cotransporter (NKCC1) localizes to the basolateral membrane of the α-intercalated cell. The purpose of this study was to determine whether rat outer medullary collecting duct (OMCD) secretes Cl− and whether transepithelial Cl− transport occurs, in part, through Cl− uptake across the basolateral membrane mediated by NKCC1 in series with Cl− efflux across the apical membrane. OMCD tubules from rats treated with deoxycorticosterone pivalate were perfused in vitro in symmetrical HCO[Formula: see text]/CO2-buffered solutions. Cl− secretion was observed in this segment, accompanied by a lumen positive transepithelial potential. Bumetanide (100 μM), when added to the bath, reduced Cl− secretion by 78%, although the lumen positive transepithelial potential and fluid flux were unchanged. Bumetanide-sensitive Cl− secretion was dependent on extracellular Na+ and either K+ or NH[Formula: see text], consistent with the ion dependency of NKCC1-mediated Cl− transport. In conclusion, OMCD tubules from deoxycorticosterone pivalate-treated rats secrete Cl−into the luminal fluid through NKCC1-mediated Cl− uptake across the basolateral membrane in series with Cl− efflux across the apical membrane. The physiological role of NKCC1-mediated Cl− uptake remains to be determined. However, the role of NKCC1 in the process of fluid secretion could not be demonstrated.

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