scholarly journals Immunocytochemical identification of low-affinity NTS2 neurotensin receptors in parietal cells of human gastric mucosa

2006 ◽  
Vol 191 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Stefan Schulz ◽  
Christoph Röcken ◽  
Matthias P A Ebert ◽  
Solveig Schulz
Keyword(s):  
Plasma Membrane ◽  
Gastric Mucosa ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cells ◽  
Neuroendocrine Cells ◽  
Target Cells ◽  
Human Gastric Mucosa ◽  
Western Blots

The biological effects of neurotensin (NT) are mediated by two distinct G protein-coupled receptors, NTS1 and NTS2. Although it is well established that neurotensin inhibits gastric acid secretion in man, the plasma membrane receptor mediating these effects has not been visualized yet. We developed and characterized a novel antipeptide antibody to the carboxy-terminal region of the human NTS2 receptor. The cellular and subcellular distribution of NTS2 receptors was evaluated in various human gastrointestinal tissues. Specificity of the antiserum was demonstrated by (1) detection of a broadband migrating at Mr 90 000–100 000 in Western blots of membranes from NTS2-expressing tissues; (2) cell-surface staining of NTS2-transfected cells; (3) translocation of NTS2 receptor immunostaining after agonist exposure; and (4) abolition of tissue immunostaining by preadsorbtion of the antibody with its immunizing peptide. In the gastrointestinal tract, NTS2 receptor immunoreactivity was highly abundant in parietal cells of the gastric mucosa, in neuroendocrine cells of the stomach small and large intestine, and in cells of the exocrine pancreas. NTS2 receptors were clearly located in the plasma membrane and uniformly present on nearly all target cells. The presence of NTS2 receptors was rarely detected in human tumors. This is the first localization of NTS2 receptors in human formalin-fixed, paraffin-embedded tissues at the cellular level. The abundant expression of low-affinity NTS2 receptors on the plasma membrane of human parietal cells provides a morphological substrate for the direct inhibition of gastric acid secretion observed after i.v. administration of neurotensin.

Nitric oxide inhibits gastric acid secretion by increasing intraparietal cell levels of cGMP in isolated human gastric glands

2005 ◽  
Vol 289 (6) ◽  
pp. G1061-G1066 ◽  
Author(s):  
Anna Berg ◽  
Stefan Redéen ◽  
Magnus Grenegård ◽  
Ann-Charlott Ericson ◽  
Sven Erik Sjöstrand
Keyword(s):  
Nitric Oxide ◽  
Gastric Mucosa ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Enzymatic Digestion ◽  
Human Gastric Mucosa ◽  
Gastric Glands ◽  
Oxyntic Mucosa ◽  
No Donor

We have previously identified cells containing the enzyme nitric oxide (NO) synthase (NOS) in the human gastric mucosa. Moreover, we have demonstrated that endogenous and exogenous NO has been shown to decrease histamine-stimulated acid secretion in isolated human gastric glands. The present investigation aimed to further determine whether this action of NO was mediated by the activation of guanylyl cyclase (GC) and subsequent production of cGMP. Isolated gastric glands were obtained after enzymatic digestion of biopsies taken from the oxyntic mucosa of healthy volunteers. Acid secretion was assessed by measuring [14C]aminopyrine accumulation, and the concentration of cGMP was determined by radioimmunoassay. In addition, immunohistochemistry was used to examine the localization of cGMP in mucosal preparations after stimulation with the NO donor S-nitroso- N-acetylpenicillamine (SNAP). SNAP (0.1 mM) was shown to decrease acid secretion stimulated by histamine (50 μM); this effect was accompanied by an increase in cGMP production, which was histologically localized to parietal cells. The membrane-permeable cGMP analog dibuturyl-cGMP (db-cGMP; 0.1–1 mM) dose dependently inhibited acid secretion. Additionally, the effect of SNAP was prevented by preincubating the glands with the GC inhibitor 4 H-8-bromo-1,2,4-oxadiazolo[3,4-d]benz[b][1,4]oxazin-1-one (10 μM). We therefore suggest that NO in the human gastric mucosa is of physiological importance in regulating acid secretion. Furthermore, the results show that NO-induced inhibition of gastric acid secretion is a cGMP-dependent mechanism in the parietal cell involving the activation of GC.

No Potassium, No Acid: K+ Channels and Gastric Acid Secretion

Physiology ◽  
2007 ◽  
Vol 22 (5) ◽  
pp. 335-341 ◽  
Author(s):  
Dirk Heitzmann ◽  
Richard Warth
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cells ◽  
Pivotal Role ◽  
K Channels

The gastric H+-K+-ATPase pumps H+ into the lumen and takes up K+ in parallel. In the acid-producing parietal cells, luminal KCNE2/KCNQ1 K+ channels play a pivotal role in replenishing K+ in the luminal fluid. Inactivation of KCNE2/KCNQ1 channels abrogates gastric acid secretion and dramatically modifies the architecture of gastric mucosa.

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.

Neuronal nitric oxide synthase: expression in rat parietal cells

2001 ◽  
Vol 280 (2) ◽  
pp. G308-G313 ◽  
Author(s):  
Shyamal Premaratne ◽  
Chun Xue ◽  
John M. McCarty ◽  
Muhammad Zaki ◽  
Robert W. McCuen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Intracellular Signaling ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Parietal Cells ◽  
Nadph Diaphorase ◽  
Rt Pcr ◽  
Oxyntic Mucosa

Nitric oxide synthases (NOS) are enzymes that catalyze the generation of nitric oxide (NO) from l-arginine and require nicotinamide adenine dinucleotide phosphate (NADPH) as a cofactor. At least three isoforms of NOS have been identified: neuronal NOS (nNOS or NOS I), inducible NOS (iNOS or NOS II), and endothelial NOS (eNOS or NOS II). Recent studies implicate NO in the regulation of gastric acid secretion. The aim of the present study was to localize the cellular distribution and characterize the isoform of NOS present in oxyntic mucosa. Oxyntic mucosal segments from rat stomach were stained by the NADPH-diaphorase reaction and with isoform-specific NOS antibodies. The expression of NOS in isolated, highly enriched (>98%) rat parietal cells was examined by immunohistochemistry, Western blot analysis, and RT-PCR. In oxyntic mucosa, histochemical staining revealed NADPH-diaphorase and nNOS immunoreactivity in cells in the midportion of the glands, which were identified as parietal cells in hematoxylin and eosin-stained step sections. In isolated parietal cells, decisive evidence for nNOS expression was obtained by specific immunohistochemistry, Western blotting, and RT-PCR. Cloning and sequence analysis of the PCR product confirmed it to be nNOS (100% identity). Expression of nNOS in parietal cells suggests that endogenous NO, acting as an intracellular signaling molecule, may participate in the regulation of gastric acid secretion.

Potassium channel KCNJ15 is required for histamine-stimulated gastric acid secretion

2015 ◽  
Vol 309 (4) ◽  
pp. C264-C270 ◽  
Author(s):  
Jianye Yuan ◽  
Wensheng Liu ◽  
Serhan Karvar ◽  
Susan S. Baker ◽  
Wenjun He ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Apical Membrane ◽  
Imaging System ◽  
Parietal Cells ◽  
Live Cells ◽  
Protein Levels ◽  
Endogenous Protein ◽  
Luminal Side

Gastric acid secretion is mediated by the K+-dependent proton pump (H+,K+-ATPase), which requires a continuous supply of K+ at the luminal side of the apical membrane. Several K+ channels are implicated in gastric acid secretion. However, the identity of the K+ channel(s) responsible for apical K+ supply is still elusive. Our previous studies have shown the translocation of KCNJ15 from cytoplasmic vesicles to the apical membrane on stimulation, indicating its involvement in gastric acid secretion. In this study, the stimulation associated trafficking of KCNJ15 was observed in a more native context with a live cell imaging system. KCNJ15 molecules in resting live cells were scattered in cytoplasm but exhibited apical localization after stimulation. Furthermore, knocking down KCNJ15 expression with a short hairpin RNA adenoviral construct abolished histamine-stimulated acid secretion in rabbit primary parietal cells. Moreover, KCNJ15, like H+,K+-ATPase, was detected in all of the parietal cells by immunofluorescence staining, whereas only about half of the parietal cells were positive for KCNQ1 under the same condition. Consistently, the endogenous protein levels of KCNJ15, analyzed by Western blotting, were higher than those of KCNQ1 in the gastric mucosa of human, mouse, and rabbit. These results provide evidence for a major role of KCNJ15 in apical K+ supply during stimulated acid secretion.

Effect of thyroid on gastric secretion and metabolism

1961 ◽  
Vol 201 (3) ◽  
pp. 567-570 ◽  
Author(s):  
E. S. Nasset ◽  
Dale P. J. Goldsmith
Keyword(s):  
Oxygen Consumption ◽  
Gastric Mucosa ◽  
Gastric Secretion ◽  
Thyroid Hormones ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Early Summer ◽  
Tissue Concentrations ◽  
Oxygen Ratio

The effect of administration of thyroid products on gastric acid secretion and metabolism was studied in dogs with gastric pouches and in gastric mucosa from rats and frogs. Whole thyroid, thyroxin, triiodothyronine, and iodinated casein generally reduced secretion in thyroidectomized dogs and in dogs with intact thyroids. The thyroid substances elevated BMR above euthyroid levels in normal dogs but not always in thyroidectomized dogs. In dogs with intact thyroids 2,4-dinitrophenol raised oxygen consumption but did not affect secretion. Whole thyroid elevated BMR in rats and frogs but did not change resting mucosal oxygen consumption. During spring and early summer thyroid feeding reduced histamine-stimulated acid secretion and mucosal oxygen consumption during secretion in frogs, but the acid-to-oxygen ratio was unaffected. These findings suggest that elevated tissue concentrations of thyroid hormones reduce the ability of the gastric mucosa to mobilize secretory energy in response to a stimulus. This effect of the thyroid hormones is apparently not directly correlated with their calorigenic properties.

Impaired gastric acid secretion in mast cell-deficient mice

1990 ◽  
Vol 259 (1) ◽  
pp. G41-G47 ◽  
Author(s):  
D. J. Stechschulte ◽  
D. C. Morris ◽  
R. L. Jilka ◽  
D. J. Stechschulte ◽  
K. N. Dileepan
Keyword(s):  
Mast Cell ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cells ◽  
Secretory Response ◽  
H2 Antagonist ◽  
Significant Difference ◽  
Basal Acid ◽  
Deficient Mice

Gastric acid secretion in normal (+/+) C57B1/6J mice and congeneic, mast cell-deficient (mi/mi) C57B1/6J mice was examined. The mast cell-deficient animals had approximately 50% of the normal quantity of gastric histamine and a blunted basal acid level and secretory response. These observations were noted despite the presence of parietal cells, which were normal in number and morphology. The H2-antagonist ranitidine inhibited basal acid secretion in both groups of animals. Exogenous histamine induced a significant secretory response in normal and mast cell-deficient groups, but only the secretory response in normal animals could be blocked by the H2-antagonist. Treatment of mast cell-deficient animals with histamine for seven consecutive days before stimulation did not restore the histamine response to the normal (+/+) levels. The normal animals demonstrated an acid secretory response to pentagastrin. Mast cell-deficient mice also responded to pentagastrin, but the response was less than that observed in the normal animals, and a significant difference was not evident in all experiments. Furthermore, simultaneous injection of mast cell-deficient animals with histamine and pentagastrin did not restore pentagastrin responsiveness to normal levels, although the histamine concentration used was sufficient to raise acid secretion to basal levels of normal mice. These results support the conclusion that non-mast cell histamine only partially contributes to basal gastric acid secretion and is insufficient to facilitate full parietal cell responsiveness. Furthermore, pentagastrin requires the presence of mast cells to elicit a maximal secretory response but can use non-mast cell histamine to activate the parietal cells for acid secretion.

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