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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastric enterochromaffin-like (ECL) cells release histamine upon stimulation with gastrin in a calcium-dependent manner. The intracellular mechanisms and proteins mediating exocytosis of histamine-containing vesicles in ECL cells have not been determined yet. We used immunocytochemistry to show the localization of SNAP-25 (synaptosome-associated protein of 25 kDa) and synaptobrevin VAMP (vesicle-associated membrane protein) in ECL cells of the rat gastric mucosa and in isolated, highly enriched ECL cells, which were identified with an antibody directed against the marker enzyme histidine decarboxylase. Immunoblots of isolated ECL cells demonstrated the presence of SNAP-25, synaptobrevin, synaptophysin, synaptotagmin, and syntaxin. Histamine release from isolated ECL cells permeabilized with 8 microM digitonin (2 min) was stimulated approximately 2.5-fold upon exposure to calcium (30 microM; 10-min incubation). Preincubation with 1 microM tetanus toxin light chain for 15 min attenuated calcium-induced histamine release by 40-50% and almost completely cleaved synaptobrevin. Botulinum neurotoxin A (100 nM) totally blocked calcium-induced histamine release and cleaved SNAP-25. We conclude that synaptobrevin, synaptophysin, synaptotagmin, SNAP-25, and syntaxin are present in gastric ECL cells. Inhibition of histamine secretion by clostridial neurotoxins associated with the cleavage of synaptobrevin and SNAP-25 implicates the functional importance of these proteins in the docking and fusion of histamine vesicles.
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PMID:Functional importance of synaptobrevin and SNAP-25 during exocytosis of histamine by rat gastric enterochromaffin-like cells. 938 39

SNARE proteins - rab3A - parietal cells - H+/K+-ATPase When stimulated by histamine, acetylcholine, or gastrin the luminal compartments of oxyntic parietal cells display conspicuous morphological changes. The luminal plasma membrane surface becomes greatly expanded, while the cytoplasmic tubulovesicles are decreased in parallel. Due to these membrane rearrangements the H+/K(+)-ATPase obtains access to the luminal surface, where proton secretion occurs. The stimulation-induced translocation of H+/K(+)-ATPase involves a fusion process. Exocytotic membrane fusion in neurons is achieved by the highly regulated interaction of mainly three proteins, the vesicle protein synaptobrevin and the plasma membrane proteins syntaxin and SNAP25 (synaptosomal-associated protein of 25 kDa), also referred to as SNARE proteins. Using immunofluorescence microscopy we analysed the subcellular distribution of neuronal synaptic proteins and rab3A in resting and stimulated parietal cells from pig and rat. In resting cells all synaptic proteins colocalized with the H+/ K(+)-ATPase trapped in the tubulovesicular compartment. After stimulation, translocated H+/K(+)-ATPase showed a typical canalicular distribution. Syntaxin, synaptobrevin, SNAP25 and rab3A underwent a similar redistribution in stimulated cells and consequently localized to the canalicular compartment. Using immunoprecipitation we found that the SNARE complex consisting of synaptobrevin, syntaxin and SNAP25, which is a prerequisite for membrane fusion in neurons, is also assembled in parietal cells. In addition the parietal cell-derived synaptobrevin could be proteolytically cleaved by tetanus toxin light chain. These data may provide evidence that SNARE proteins and rab3A are functionally involved in the stimulation-induced translocation of the H+/K(+)-ATPase.
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PMID:SNARE proteins and rab3A contribute to canalicular formation in parietal cells. 1060 54

Enterochromaffin-like (ECL) cells are neuroendocrine cells in the gastric mucosa that control acid secretion by releasing histamine as a paracrine stimulant. The antral hormone gastrin and the neural messenger pituitary adenylyl cyclase-activating peptide (PACAP) potently stimulate histamine synthesis, storage, and secretion by ECL cells. Histamine is stored in secretory vesicles via V-type ATPases and vesicular monoamine transporters of subtype 2 (VMAT-2). Plasmalemmal calcium entry occurs via L-type calcium channels upon stimulation with secretagogues. K(+) and Cl(-) channels maintain the membrane potential. Calcium-triggered exocytosis of histamine is mediated by interacting SNARE proteins, especially by synaptobrevin and SNAP-25. Dynamins and amphiphysins appear to play a key role in endocytosis. ECL cells are under transcriptional control of various hormones. Gastrin stimulates transcriptional activity of the histidine decarboxylase (HDC), VMAT-2, and chromogranin A promoter by activation of Sp1 elements and CREB. During chronic Helicobacter pylori infection, pro-inflammatory cytokines are released that can also affect ECL cells, thus impairing their secretory function and viability, which can predispose to hypochlorhydria and gastric carcinogenesis.
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PMID:Physiology of gastric enterochromaffin-like cells. 1222 Nov 95

Enterochromaffin-like (ECL) cells are neuroendocrine cells in the gastric epithelium characterized by numerous electron-empty, histamine-containing secretory vesicles. The antral hormone gastrin is the key stimulus of histamine secretion from this cell type, thereby controling acid secretion. Following receptor binding, gastrin activates a biphasic calcium signal in ECL cells that involves activation of inositol triphosphate receptors and calcium entry across the plasma membrane. Dihydropyridines block gastrin-induced histamine secretion. However, no depolarization was observed following stimulation with gastrin. Elevation of intracellular calcium by gastrin is an important prerequisite for exocytosis. In permeabilized ECL cells, addition of calcium results in histamine release, which can be inhibited by tetanus toxin and botulinum neurotoxin A, underlining the functional importance of the synaptosome-associated protein of 25 kDa (SNAP-25) and synaptobrevin. Immunocytochemistry also confirmed the presence of these SNAP receptor (SNARE) proteins, as well as synaptophysin, synaptotagmin, and syntaxin. Following 3-6 h of incubation in isolated cells, several transcription factors are induced by gastrin, such as ERK1/2, Sp1, and CRE. Gastrin thereby directly stimulates transcription of the vesicular monoamine transporter subtype 2 (VMAT-2) and chromogranins. Gene expression of histidine decarboxylase (HDC) appears to be stimulated by a putative "gastrin-responsive" element adjacent to the HDC exon 1 gene. ECL cells thereby share several similarities with adrenal chromaffin cells and neurons, but have their own functional properties. Gastrin coordinates secretion, synthesis, and storage by activating diverging signal transducers, leading to a functional synergy in this cell type.
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PMID:Circle of life of secretory vesicles in gastric enterochromaffin-like cells. 1243 57