Enhanced calcium signaling and acid secretion in parietal cells isolated from gastrin-deficient mice

2003 ◽  
Vol 284 (1) ◽  
pp. G145-G153 ◽  
Author(s):  
Karen L. Hinkle ◽  
Gina C. Bane ◽  
Ali Jazayeri ◽  
Linda C. Samuelson
Keyword(s):  
Acid Secretion ◽  
Parietal Cell ◽  
Mutant Cell ◽  
Flow Cytometric Analysis ◽  
Cell Number ◽  
Parietal Cells ◽  
Gastric Glands ◽  
Deficient Mice ◽  
Cell Defect

Gastrin-deficient mice have impaired basal and agonist-stimulated gastric acid secretion. To analyze whether an intrinsic parietal cell defect contributed to the reduced acid secretion, we analyzed parietal cell calcium responses and acid secretory function in vitro. Parietal cells were purified by light-scatter cell sorting and calcium responses to gastrin, histamine, and carbachol were measured in gastrin-deficient and wild-type mice cell preparations. Surprisingly, basal and histamine-induced calcium concentrations were higher in the mutant cell preparations. [14C]aminopyrine uptake analysis in acutely isolated gastric glands revealed that basal acid accumulation was enhanced in gastrin-deficient cell preparations as well as on treatment with carbachol or histamine. These results suggested that an intrinsic parietal cell defect was not responsible for the reduced acid secretion in gastrin-deficient mice. Flow cytometric analysis of dispersed, H+-K+-ATPase-immunostained gastric mucosal preparations revealed a marked increase in parietal cell number in gastrin-deficient mice, which may have accounted for the enhanced in vitro acid secretion detected in this study. Parietal cells were found to be significantly smaller in the mutant cell preparations, suggesting that gastrin stimulation modulates parietal cell morphology.

Inhibitory action of somatostatin on isolated gastric glands and parietal cells

1983 ◽  
Vol 245 (2) ◽  
pp. G221-G229 ◽  
Author(s):  
C. S. Chew
Keyword(s):  
Parietal Cell ◽  
Inhibitory Action ◽  
Parietal Cells ◽  
Acid Formation ◽  
Gastric Glands ◽  
Isolated Gastric Glands ◽  
Cell Acid ◽  
Kinetics Of ◽  
Apparent Ic50

The action of somatostatin in vitro was characterized using glands and parietal cells isolated from rabbit gastric mucosa. In the presence of the reducing agent dithiothreitol, somatostatin was found to inhibit gastrin- and histamine-stimulated acid formation in glands as measured by [14C]aminopyrine (AP) accumulation and oxygen consumption, both measurements that appear to be reliable indexes of parietal cell acid formation. In glands the inhibition of the secretory response to gastrin was more potent (60-80%) than that to histamine (15-25%). The kinetics of somatostatin inhibition of responses to both agents were noncompetitive. The apparent IC50 for the partial somatostatin inhibition of histamine-stimulated AP accumulation was similar to that for gastrin (approx 3 X 10(-9) M) when maximum concentrations of histamine (10(-4) M) or gastrin (10(-7) M) were used. The inhibitory action of somatostatin appeared to be specific, inasmuch as this peptide had no significant effect on basal secretion or secretion stimulated by carbachol, dibutyryl cAMP, cholera toxin, or elevated extracellular K+. In purified parietal cell preparations, somatostatin inhibited histamine- but not gastrin-stimulated AP accumulation. Moreover, the inhibition of histamine-stimulated AP accumulation in parietal cells was more pronounced than in glands. These results suggest that somatostatin acts directly on parietal cells to inhibit histamine activation of H+ secretion. Somatostatin also acts indirectly to inhibit gastrin, perhaps by blocking the release of histamine from paracrine- or endocrinelike cells present in the glands.

Impaired gastric acid secretion in gastrin-deficient mice

1998 ◽  
Vol 274 (3) ◽  
pp. G561-G568 ◽  
Author(s):  
Lennart Friis-Hansen ◽  
Frank Sundler ◽  
Ying Li ◽  
Patrick J. Gillespie ◽  
Thomas L. Saunders ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Histidine Decarboxylase ◽  
Embryonic Stem ◽  
Parietal Cells ◽  
Gastric Glands ◽  
Partial Restoration ◽  
Ecl Cells ◽  
Deficient Mice

To further understand the role of the peptide hormone gastrin in the development and function of the stomach, we have generated gastrin-deficient mice by gene targeting in embryonic stem cells. Mutant mice were viable and fertile, without obvious visible abnormalities. However, gastric function was severely affected by the loss of gastrin. Basal gastric acid secretion was abolished and could not be induced by histamine, carbachol, or gastrin. Histological analysis revealed alterations in the two cell types primarily involved in acid secretion, parietal and enterochromaffin-like (ECL) cells. Parietal cells were reduced in number with an accumulation of immature cells lacking H+-K+-adenosinetriphosphatase (H+-K+-ATPase). ECL cells were positioned closer to the base of the gastric glands, with markedly lower expression of histidine decarboxylase. Gastrin administration for 6 days reversed the effects of the gastrin deficiency, leading to an increase in the number of mature, H+-K+-ATPase-positive parietal cells and a partial restoration of acid secretion. The results show that gastrin is critically important for the function of the acid secretory system.

Characterization of a gastrin-type receptor on rabbit gastric parietal cells using L365,260 and L364,718

1991 ◽  
Vol 260 (2) ◽  
pp. G182-G188
Author(s):  
S. Roche ◽  
J. P. Bali ◽  
J. C. Galleyrand ◽  
R. Magous
Keyword(s):  
Acid Secretion ◽  
Parietal Cell ◽  
Inositol Phosphates ◽  
Secretory Activity ◽  
Receptor Activation ◽  
Parietal Cells ◽  
Receptor Sites ◽  
Gastric Parietal Cells ◽  
Type Receptor

Previous studies have demonstrated that gastrin and the COOH-terminal octapeptide of cholecystokinin (CCK-8) stimulated in vitro acid secretion from isolated rabbit gastric parietal cells. Both peptides bind to receptor sites located on these cells and induce an increase in phosphoinositide turnover and an uptake of [14C]aminopyrine ([14C]AP) with the same efficacy and potency. In the present study, we used the 3-(benzoylamino)-benzodiazepine analogue L365,260 and the 3-(acylamino)-benzodiazepine analogue L364,718 to investigate what type of receptor (gastrin type or CCK-A type) is involved in the regulation of the H+ secretory activity of the rabbit parietal cell. Neither L365,260 nor L364,718 alone caused stimulation of [3H]inositol phosphates ([3H]InsP) production. Each analogue inhibited 125I-labeled gastrin or 125I-CCK-8 binding to parietal cells and gastrin- or CCK-8-induced [3H]InsP production and [14C]AP accumulation. In all cases, L365,260 was approximately 70-100 times more potent than L364,718 (IC50 approximately 2-4 nM for L365,260 and approximately 0.2-0.4 microM for L364,718). Nevertheless, each antagonist displayed the same potency to inhibit the effects of gastrin or CCK-8. These results demonstrate that gastrin and CCK-8 interact with the same "gastrin-type" receptor on parietal cells. Moreover, L365,260 behaves as a competitive antagonist of the action of gastrin on parietal cells. Gastrin induces a rise in the levels of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4] within the first seconds after parietal cell stimulation. The fact that L365,260 (10 nM) totally suppressed the gastrin-induced formation of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 suggests the involvement of these isomers in the mediation of acid secretion through gastrin receptor activation.

State of actin in gastric parietal cells

1998 ◽  
Vol 274 (1) ◽  
pp. C97-C104 ◽  
Author(s):  
John G. Forte ◽  
Bernice Ly ◽  
Qinfen Rong ◽  
Shoji Ogihara ◽  
Marlon Ramilo ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Parietal Cell ◽  
Parietal Cells ◽  
Secretory Process ◽  
Cell Protein ◽  
Cell Secretion ◽  
Gastric Glands ◽  
Western Blot Assay ◽  
Deoxyribonuclease I ◽  
Gastric Parietal Cells

Remodeling of the apical membrane-cytoskeleton has been suggested to occur when gastric parietal cells are stimulated to secrete HCl. The present experiments assayed the relative amounts of F-actin and G-actin in gastric glands and parietal cells, as well as the changes in the state of actin on stimulation. Glands and cells were treated with a Nonidet P-40 extraction buffer for separation into detergent-soluble (supernatant) and detergent-insoluble (pellet) pools. Two actin assays were used to quantitate actin: the deoxyribonuclease I binding assay to measure G-actin and F-actin content in the two pools and a simple Western blot assay to quantitate the relative amounts of actin in the pools. Functional secretory responsiveness was assayed by aminopyrine accumulation. About 5% of the total parietal cell protein is actin, with about 90% of the actin present as F-actin. Stimulation of acid secretion resulted in no measurable change in the relative amounts of G-actin and cytoskeletal F-actin. Treatment of gastric glands with cytochalasin D inhibited acid secretion and resulted in a decrease in F-actin and an increase in G-actin. No inhibition of parietal cell secretion was observed when phalloidin was used to stabilize actin filaments. These data are consistent with the hypothesis that microfilamentous actin is essential for membrane recruitment underlying parietal cell secretion. Although the experiments do not eliminate the importance of rapid exchange between G- and F-actin for the secretory process, the parietal cell maintains actin in a highly polymerized state, and no measurable changes in the steady-state ratio of G-actin to F-actin are associated with stimulation to secrete acid.

Probes of parietal cell function

1980 ◽  
Vol 238 (3) ◽  
pp. G165-G176 ◽  
Author(s):  
T. Berglindh ◽  
D. R. Dibona ◽  
S. Ito ◽  
G. Sachs
Keyword(s):  
Acid Secretion ◽  
Parietal Cell ◽  
Cell Function ◽  
Parietal Cells ◽  
Differential Interference Contrast ◽  
Green Fluorescence ◽  
Weak Base ◽  
Gastric Glands ◽  
High K ◽  
High Concentrations

The site of acid secretion in the gastric mucosa has been inferred, but never proven. Using differential interference-contrast (Nomarski) microscopy an expansion of intracellular vacuoles was observed in the parietal cells of living rabbit gastric glands following histamine stimulation. A similar vacuolization occurring only in part of a parietal cell population could be induced by high concentrations of accumulated weak base, aminopyrine, in the absence of secretagogue. In high-K+ medium, 10(-3) M aminopyrine induced massive vacuolization in all parietal cells, consistent with the strong effect of high K+ in stimulating aminopyrine uptake by isolated glands. Electron micrographs showed that the apparent vacuoles correspond to the secretory canaliculi in various stages of swelling. Acridine orange, a fluorescent dye which is distributed across natural membranes as a function of a pH gradient and binds in a multimolecular fashion (stacking) to negative sites, was accumulated by gastric glands as a function of acid secretion. Visualization of such glands by fluorescence or a combination of Nomarski and fluorescence microscopy showed a red fluorescence in the expanding secretory canaliculi that was in sharp contrast to the green fluorescence in the rest of the cell. From these data it is concluded that the site of acid secretion is indeed the secretory canaliculus of the parietal cell. It is also possible that the formation of secretory canaliculi may be induced osmotically and that the peripheral "parietal" position and triangular shape of the parietal cell is necessary to allow expansion and oriented apical flow of HCl.

scholarly journals Cytodifferentiation of the postnatal mouse stomach in normal and Huntingtin-interacting protein 1-related-deficient mice

2010 ◽  
Vol 299 (6) ◽  
pp. G1241-G1251 ◽  
Author(s):  
Theresa M. Keeley ◽  
Linda C. Samuelson
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Parietal Cell ◽  
Parietal Cells ◽  
Gastric Epithelial Cells ◽  
Wild Type ◽  
Gastric Glands ◽  
Interacting Protein ◽  
Huntingtin Interacting Protein ◽  
Deficient Mice

Huntingtin-interacting protein 1-related (Hip1r) is highly expressed in gastric parietal cells, where it participates in vesicular trafficking associated with acid secretion. Hip1r-deficient mice have a progressive remodeling of the mucosa, including apoptotic loss of parietal cells, glandular hypertrophy, mucous cell metaplasia, and reduced numbers of zymogenic cells. In this study, we characterized gastric gland development in wild-type and Hip1r-deficient mice to define normal development, as well as the timing and sequence of the cellular transformation events in the mutant stomach. Postnatal (newborn to 8-wk-old) stomachs were examined by histological and gene expression analysis. At birth, gastric glands in wild-type and mutant mice were rudimentary and mature gastric epithelial cells were not apparent, although marker expression was detected for most cell lineages. Interestingly, newborns exhibited unusual cell types, including a novel surface cell filled with lipid and cells that coexpressed markers of mature mucous neck and zymogenic cells. Glandular morphogenesis proceeded rapidly in both genotypes, with gastric glands formed by weaning at 3 wk of age. In the Hip1r-deficient stomach, epithelial cell remodeling developed in a progressive manner. Initially, in the perinatal stomach, cellular changes were limited to parietal cell apoptosis. Other epithelial cell changes, including apoptotic loss of zymogenic cells and expansion of metaplastic mucous cells, emerged several weeks later when the glands were morphologically mature. Thus, parietal cell loss appeared to be the initiating event in Hip1r-deficient mice, with secondary remodeling of the other gastric epithelial cells.

scholarly journals CORRELATION OF THE FINE STRUCTURE OF THE GASTRIC PARIETAL CELL (DOG) WITH FUNCTIONAL ACTIVITY OF THE STOMACH

1961 ◽  
Vol 11 (2) ◽  
pp. 349-363 ◽  
Author(s):  
A. W. Sedar ◽  
M. H. F. Friedman
Keyword(s):  
Fine Structure ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cell ◽  
Parietal Cells ◽  
Gastric Glands ◽  
Secretory Cycle ◽  
Thin Sections ◽  
Acid Secreting

The fine structure of the parietal (oxyntic) cell in the gastric glands (corpus of the stomach) of the dog was examined under conditions of active gastric acid secretion and compared with cellular structure in the non-acid-secretory (basal) state. Animals, in both acute and chronic experiments, were equipped with gastric fistulae so that gastric juice could be collected for analysis of total acidity, free acidity, volume, and pH prior to biopsy of the gastric mucosa. The specimens of mucosa were fixed in buffered OsO4 and embedded in n-butyl methacrylate and the thin sections were stained with lead hydroxide before examination in the electron microscope. A majority of parietal cells showed an alteration of fine structure during stimulation of gastric acid secretion by a number of different techniques (electrical vagal stimulation, histamine administration, or insulin injection). The changes in fine structure affected mainly the smooth surfaced vesicular elements and the intracellular canaliculi in the cytoplasm of the cell. The mitochondria also appeared to be involved to some extent. During acid secretion a greater concentration of smooth surface profiles is found adjacent to the walls of the intracellular canaliculi; other parietal cells exhibited a marked decrease in number of smooth surfaced elements. Intracellular canaliculi, always present in non-acid-secreting oxyntic cells, develop more extensively in cells of acid-secreting gastric glands. The surface area of these canaliculi is greatly increased by the elaboration of a large number of closely approximated and elongated microvilli. Still other parietal cells apparently in a different stage of the secretory cycle exhibit non-patent canaliculi lacking prominence; such cells have very few smooth surfaced vesicular elements. These morphological findings correlated with the acid-secretory state of the stomach provide evidence that the parietal cell participates in the process of acid secretion.

scholarly journals Gene expression profiling of gastrin target genes in parietal cells

2006 ◽  
Vol 24 (2) ◽  
pp. 124-132 ◽  
Author(s):  
Renu N. Jain ◽  
Cynthia S. Brunkan ◽  
Catherine S. Chew ◽  
Linda C. Samuelson
Keyword(s):  
Gene Expression ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cell ◽  
Target Genes ◽  
Adaptor Protein ◽  
Parietal Cells ◽  
Cell Gene Expression ◽  
Cell Gene

Previous studies demonstrated that mice with a null mutation in the gene encoding the hormone gastrin have impaired gastric acid secretion. Hence, the aim of this study was to evaluate changes in the acid-secreting parietal cell in gastrin-deficient (GAS-KO) mice. Analysis of several transcripts encoding parietal cell proteins involved in gastric acid secretion showed reduced abundance in the GAS-KO stomach, including H+,K+-ATPase α- and β-subunits, KCNQ1 potassium channel, aquaporin-4 water channel, and creatine kinase B, which were reversed by gastrin infusion for 1 wk. Although mRNA and protein levels of LIM and SH3 domain-containing protein-1 (LASP-1) were not greatly changed in the mutant, there was a marked reduction in phosphorylation, consistent with its proposed role as a cAMP signal adaptor protein associated with acid secretion. A more comprehensive analysis of parietal cell gene expression in GAS-KO mice was performed using the Affymetrix U74AV2 chip with RNA from parietal cells purified by flow cytometry to >90%. Comparison of gene expression in GAS-KO and wild-type mice identified 47 transcripts that differed by greater than or equal to twofold, suggesting that gastrin affects parietal cell gene expression in a specific manner. The differentially expressed genes included several genes in signaling pathways, with a substantial number (20%) known to be target genes for Wnt and Myc.

Functionally distinct pools of actin in secretory cells

2001 ◽  
Vol 281 (2) ◽  
pp. C407-C417 ◽  
Author(s):  
David A. Ammar ◽  
Phuong N. B. Nguyen ◽  
John G. Forte
Keyword(s):  
Parietal Cell ◽  
Cultured Cells ◽  
Parietal Cells ◽  
Secretory Cells ◽  
Resting Cells ◽  
Gastric Glands ◽  
Gastric Parietal Cell ◽  
Actin Organization ◽  
Isolated Gastric Glands ◽  
High Concentrations

Acid secretion by the gastric parietal cell is controlled through movement of vesicles containing the proton pump, the H+-K+-ATPase (HK). We have used latrunculin B (Lat B), which binds to monomeric actin, to investigate actin turnover in the stimulated parietal cell. In isolated gastric glands, relatively high concentrations of Lat B were required to inhibit acid accumulation (ED50∼70 μM). Cultured parietal cells stimulated in the presence of low Lat B (0.1–1 μM) have reduced lamellipodia formation and some aberrant punctate phalloidin-stained structures, but translocation of HK and vacuolar swelling appeared unaffected. High Lat B (10–50 μM) resulted in gross changes in actin organization (punctate phalloidin-stained structures throughout the cell and nucleus) and reduced translocation of HK and vacuolar swelling. Resting parietal cells treated with high Lat B showed minor effects on morphology and F-actin staining. If resting cells treated with high Lat B were washed immediately before stimulation, they exhibited a normal stimulated morphology. These data suggest distinct pools of parietal cell actin: a pool highly susceptible to Lat B primarily involved in motile function of cultured cells; and a Lat B-resistant pool, most likely microvillar filaments, that is essential for secretion. Furthermore, the stimulation process appears to accentuate the effects of Lat B, most likely through Lat B binding to monomer actin liberated by the turnover of the motile actin filament pool.

scholarly journals Localization of ClC-2 Cl− channels in rabbit gastric mucosa

2001 ◽  
Vol 280 (6) ◽  
pp. C1599-C1606 ◽  
Author(s):  
Ann M. Sherry ◽  
Danuta H. Malinowska ◽  
Randal E. Morris ◽  
Georgianne M. Ciraolo ◽  
John Cuppoletti
Keyword(s):  
Gastric Mucosa ◽  
Parietal Cell ◽  
Functional Characterization ◽  
Parietal Cells ◽  
Immunogold Electron Microscopy ◽  
Gastric Glands ◽  
Canalicular Membrane ◽  
Isolated Gastric Glands ◽  
Hcl Secretion

HCl secretion across the parietal cell apical secretory membrane involves the H+-K+-ATPase, the ClC-2 Cl− channel, and a K+ channel. In the present study, the cellular and subcellular distribution of ClC-2 mRNA and protein was determined in the rabbit gastric mucosa and in isolated gastric glands. ClC-2 mRNA was localized to parietal cells by in situ hybridization and by direct in situ RT-PCR. By immunoperoxidase microscopy, ClC-2 protein was concentrated in parietal cells. Immunofluorescent confocal microscopy suggested that the ClC-2 was localized to the secretory canalicular membrane of stimulated parietal cells and to intracellular structures of resting parietal cells. Immunogold electron microscopy confirmed that ClC-2 is in the secretory canalicular membrane of stimulated cells and in tubulovesicles of resting parietal cells. These findings, together with previous functional characterization of the native and recombinant channel, strongly indicate that ClC-2 is the Cl− channel, which together with the H+-K+-ATPase and a K+ channel, results in HCl secretion across the parietal cell secretory membrane.

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