Calcium oscillations and morphological transformations in single cultured gastric parietal cells

1991 ◽  
Vol 260 (1) ◽  
pp. C67-C78 ◽  
Author(s):  
M. Ljungstrom ◽  
C. S. Chew
Keyword(s):  
Acid Secretion ◽  
Calcium Signaling ◽  
Calcium Oscillations ◽  
Parietal Cells ◽  
Cell Populations ◽  
Control Mechanisms ◽  
Light Microscope Level ◽  
Cellular Calcium ◽  
Hcl Secretion ◽  
Morphological Transformations

Calcium is an important regulator of cellular activities including HCl secretion by parietal cells. With cholinergic agonists, a role for calcium is established; however, with histamine, at least two signaling pathways may be involved including calcium and adenosine 3',5'-cyclic monophosphate (cAMP). Because chelation of medium and/or cellular calcium has pronounced inhibitory effects on cholinergic but lesser effects on histamine-stimulated acid secretory responses in cell populations, the calcium pathway may not be of central importance for HCl secretion regulated by histamine. We have used digitized video imaging of fura-2 fluorescence ratios and cellular morphology to determine more precisely the relationship between cellular calcium signaling mechanisms and acid secretion in single cultured rabbit parietal cells. Calcium signaling patterns were found to exhibit striking differences with histamine as compared with the cholinergic agonist carbachol. Maximal doses of histamine initiated repetitive oscillations in intracellular calcium ([Ca2+]i) in approximately 50% of cells, whereas the maximal carbachol response was characterized by a typical initial spike followed by a sustained elevation in [Ca2+]i. Oscillations in response to carbachol were detected only at doses below the half-maximal concentration for initiation of acid secretion. Correlation of gradual expansion of acidic vacuoles with increases in [Ca2+]i in the same cells indicated that approximately 20% of cells increased acid secretory-related activities in response to histamine with no detectable rise in [Ca2+]i. These data suggest two possibilities: 1) a rise in [Ca2+]i is not necessary for histamine-stimulated HCl secretion, or 2) heterogeneous receptor-coupling mechanisms exist in parietal cell populations with either calcium or cAMP mechanisms predominating in different subpopulations. The ability to assess simultaneously acid secretory-related responses and calcium signaling patterns allows, for the first time, correlation of "physiological" and biochemical responses in single parietal cells. This methodology is expected to provide new insight into second messenger control mechanisms that are not possible either in cell populations or acutely isolated parietal cells that do not exhibit morphological transformations detectable at the light microscope level.

Functional heterogeneity of parietal cells along the pig-gland axis

1997 ◽  
Vol 272 (1) ◽  
pp. G161-G171 ◽  
Author(s):  
S. M. Karam ◽  
X. Yao ◽  
J. G. Forte
Keyword(s):  
Acid Secretion ◽  
Gastric Gland ◽  
Longitudinal Axis ◽  
Parietal Cells ◽  
Gastric Epithelium ◽  
Functional Heterogeneity ◽  
Gastric Glands ◽  
Isolated Gastric Glands ◽  
Morphological Transformations ◽  
Stimulation Of

The gastric epithelium forms numerous short pits continuous with long tubular glands divisible into isthmus neck, and base regions. Parietal cells are produced in the isthmus and migrate down to the neck and base regions as they mature and age. Stimulation of parietal cells is manifested by translocation of H(+)-K(+)-adenosinetriphosphatase-rich tubulovesicles (TV) from the cytoplasm into the secretory-apical (SA) membrane. In this study we used rabbit isolated gastric glands to examine the physiological responses of parietal cells to graded levels of stimulation. Quantitative morphometry was used to evaluate parietal cell response along the longitudinal axis of the gland. Acid secretion as estimated by [14C]aminopyrine uptake was well correlated with parallel enzymatic and immunoblot assays for the redistribution of H(+)-K(+)-ATPase from TV to SA membranes. These responses also correlated well with morphological transformations of parietal cells within the isthmus and neck regions of the gastric gland; however, parietal cells in the base of the gland showed very little morphological change in response to any of the stimuli used. The poor responsiveness of basal parietal cells is in agreement with observations of intact mucosa and suggests that older parietal cells may serve some function other than acid secretion.

Mechanisms of cellular calcium oscillations in secretory cells

1992 ◽  
Vol 1137 (2) ◽  
pp. 197-207 ◽  
Author(s):  
Alexey V. Tepikin ◽  
Ole H. Petersen
Keyword(s):  
Calcium Oscillations ◽  
Secretory Cells ◽  
Cellular Calcium

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.

Primary culture of secretagogue-responsive parietal cells from rabbit gastric mucosa

1989 ◽  
Vol 256 (1) ◽  
pp. G254-G263 ◽  
Author(s):  
C. S. Chew ◽  
M. Ljungstrom ◽  
A. Smolka ◽  
M. R. Brown
Keyword(s):  
Gastric Mucosa ◽  
Primary Culture ◽  
Cultured Cells ◽  
Single Cells ◽  
Parietal Cells ◽  
Ultrastructural Changes ◽  
Long Term Effects ◽  
H2 Receptor Antagonist ◽  
Morphological Transformations

A new procedure for isolation and primary culture of gastric parietal cells is described. Parietal cells from rabbit gastric mucosa are enriched to greater than 95% purity by combining a Nycodenz gradient separation with centrifugal elutriation. Cells are plated on the basement membrane matrix, Matrigel, and maintained in culture for at least 1 wk. Parietal cells cultured in this manner remain differentiated, cross-react with monoclonal H+-K+-ATPase antibodies, and respond to histamine, gastrin, and cholinergic stimulation with increased acid production as measured by accumulation of the weak base, [14C]aminopyrine. When stimulated, cultured cells undergo ultrastructural changes in which intracellular canaliculi expand and numerous microvilli are observed. These ultrastructural changes are similar to those previously found to occur in vivo and in acutely isolated parietal cells. Morphological transformations in living cells can also be observed with differential interference contrast optics in the light microscope. After histamine stimulation, intracellular canaliculi gradually expand to form large vacuolar spaces. When the H2 receptor antagonist, cimetidine, is added to histamine-stimulated cells, these vacuoles gradually disappear. The ability to maintain hormonally responsive parietal cells in primary culture should make it possible to study direct, long-term effects of a variety of agonists and antagonists on parietal cell secretory-related activity. These cultured cells should also prove to be useful for the study of calcium transients, ion fluxes, and intracellular pH as related to acid secretion in single cells, particularly since morphological transformations can be used to monitor "physiological" responses at the same time within the same cell.

scholarly journals Polarized Distribution of IQGAP Proteins in Gastric Parietal Cells and Their Roles in Regulated Epithelial Cell Secretion

2003 ◽  
Vol 14 (3) ◽  
pp. 1097-1108 ◽  
Author(s):  
Rihong Zhou ◽  
Zhen Guo ◽  
Charles Watson ◽  
Emily Chen ◽  
Rong Kong ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Actin Cytoskeleton ◽  
Acid Secretion ◽  
Rho Gtpase ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Parietal Cells ◽  
Actin Dynamics ◽  
Cell Secretion ◽  
Gastric Parietal Cells

Actin cytoskeleton plays an important role in the establishment of epithelial cell polarity. Cdc42, a member of Rho GTPase family, modulates actin dynamics via its regulators, such as IQGAP proteins. Gastric parietal cells are polarized epithelial cells in which regulated acid secretion occurs in the apical membrane upon stimulation. We have previously shown that actin isoforms are polarized to different membrane domains and that the integrity of the actin cytoskeleton is essential for acid secretion. Herein, we show that Cdc42 is preferentially distributed to the apical membrane of gastric parietal cells. In addition, we revealed that two Cdc42 regulators, IQGAP1 and IQGAP2, are present in gastric parietal cells. Interestingly, IQGAP2 is polarized to the apical membrane of the parietal cells, whereas IQGAP1 is mainly distributed to the basolateral membrane. An IQGAP peptide that competes with full-length IQGAP proteins for Cdc42-binding in vitro also inhibits acid secretion in streptolysin-O-permeabilized gastric glands. Furthermore, this peptide disrupts the association of IQGAP and Cdc42 with the apical actin cytoskeleton and prevents the apical membrane remodeling upon stimulation. We propose that IQGAP2 forms a link that associates Cdc42 with the apical cytoskeleton and thus allows for activation of polarized secretion in gastric parietal cells.

Sign in / Sign up

Export Citation Format

Share Document