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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of enterochromaffin-like cells in rat stomach: effects of α-fluoromethylhistidine-evoked histamine depletion and hypergastrinemia (1996)
    Springer
    Cell & tissue research 283 (1996), S. 469-478 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Stomach ; Enterochromaffin-like cells ; Histamine ; α-Fluoromethylhistidine ; Hypergastrinemia ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Histamine-producing enterochromaffin-like (ECL) cells are numerous in the oxyntic mucosa of the rat stomach. They respond to gastrin by secretory activation, hypertrophy and hyperplasia. They contain cytoplasmic granules (median profile diameter 120 nm), secretory vesicles (180 nm) and microvesicles (70 nm). α-Fluoromethylhistidine (α-FMH) depletes histamine from the ECL cells by inhibiting the histamine-forming enzyme histidine decarboxylase. Long-term hypergastrinemia, evoked by omeprazole, increases the ECL-cell histamine concentration. The way in which chronic histamine depletion affects omeprazole-induced ECL-cell hypertrophy, and the ways in which granules and vesicles in the ECL cells respond to α-FMH and/or omeprazole have been studied. Rats were treated with α-FMH (3 mg/kg per h subcutaneously), omeprazole (400 μmol/kg per day orally), α-FMH+omeprazole, or vehicle for 6 weeks. ECL cell profiles in electron micrographs were analysed panimetrically. The results show that the omeprazole-evoked hypertrophy of the ECL cells is not affected by depletion of ECL-cell histamine, thereby supporting the view that ECL-cell histamine is not important for full expression of the gastrin-evoked trophic effects on the ECL cells. The loss of ECL-cell histamine following treatment with α-FMH and with α-FMH+omeprazole is associated with a greatly reduced size of the secretory vesicle compartment. The granules, on the other hand, are unaffected by α-FMH and α-FMH+omeprazole. Omeprazole treatment leads to the appearance of numerous vacuoles (with profile diameter greater than 500 nm); such vacuoles are not observed in the ECL cells of rats treated with α-FMH or α-FMH+omeprazole. The omeprazole-induced increase in ECL-cell histamine is associated with an increase in the compartment composed of secretory vesicles and vacuoles. The findings support the hypothesis that secretory vesicles (and vacuoles) represent a major storage site of ECL-cell histamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050558
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  • 2
    Electronic Resource
    Electronic Resource
    ECL cells of the rat stomach: development of lipofuscin in response to sustained gastrin stimulation (1998)
    Springer
    Cell & tissue research 291 (1998), S. 315-323 
    Details
    ISSN: 1432-0878
    Keywords: Key words Stomach ; ECL cells ; Gastrin ; Omeprazole ; Vacuoles ; Lipofuscin ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Ageing cells, especially post-mitotic cells, are known to accumulate pigments, i.e. highly electron-dense material, referred to as ceroid or lipofuscin. This material is formed as a consequence of autophagocytosis and peroxidation of the products undergoing degradation. The present study describes the development of lipofuscin in the ECL cells of the rat stomach. These cells produce and secrete histamine in response to gastrin. They are rich in secretory vesicles, which fuse to form vacuoles in hypergastrinaemic rats. Hypergastrinaemia was induced by continuous infusion of human Leu15-gastrin-17 for 6 days or by daily treatment with omeprazole for 10 weeks. Either treatment caused both vacuoles and lipofuscin bodies to appear in large numbers; the vacuoles disappeared promptly after interruption of the hypergastrinaemia, whereas the lipofuscin bodies remained. Antrectomy-evoked hypogastrinaemia was associated with a reduced number and volume density of lipofuscin bodies. Treatment with α-fluoromethylhistidine, an irreversible inhibitor of the histamine-forming enzyme, resulted in depletion of ECL-cell histamine and was found to prevent the omeprazole-evoked formation of vacuoles and lipofuscin. The numbers of both vacuoles and lipofuscin bodies were well-correlated with the serum gastrin concentration, suggesting that gastrin stimulates the development not only of vacuoles but also of lipofuscin, perhaps through enhanced autophagocytosis and/or oxidative stress. Thus, lipofuscin bodies may develop from vacuoles, and both vacuoles and lipofuscin bodies may reflect the efforts of overstimulated ECL cells to cope with the excessive formation of secretory products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051001
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  • 3
    Electronic Resource
    Electronic Resource
    Exocytotic proteins in enterochromaffin-like (ECL) cells of the rat stomach (1997)
    Springer
    Cell & tissue research 290 (1997), S. 539-551 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Exocytotic proteins ; Synaptophysin ; Synaptotagmin ; Syntaxin ; Secretory granule ; Histidine decarboxylase (HDC) ; Immunohistochemistry ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Proteins participating in vesicular docking and fusion have been identified in the nervous system. Such proteins appear to be important for the molecular regulation of exocytosis also in non-neuronal cells. The enterochromaffin-like (ECL) cells of the gastric acid-secreting (oxyntic) mucosa secrete histamine and chromogranin A-derived peptides, such as pancreastatin. Using immunohistochemistry, we have examined whether the ECL cells of the rat stomach, identified with antibodies to histidine decarboxylase (HDC, the histamine-forming enzyme), express the same exocytotic proteins as neurons. The ECL cells displayed immunoreactivity for synaptophysin, synaptotagmin III, vesicle-associated membrane protein-2 (VAMP-2), cysteine string protein (CSP), vesicular monoamine transporter-2 (VMAT-2), synaptosomal-associated protein of 25 kDa (SNAP-25), syntaxin, and Munc-18, but not for synaptotagmin I/II and VAMP-1. Synaptophysin and VMAT-2 could be detected not only in the ECL cells, but also in a population of HDC-negative cells. The demonstration of synaptotagmin III in only a limited number of ECL cells suggests the existence of a subpopulation of ECL cells. The results show that several exocytotic proteins, previously identified in neurons, are present in rat stomach ECL cells. Hence, proteins engaged in vesicular docking and in the fusion of granule/vesicle membrane with plasma membrane seem to exist in both neurons and endocrine cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050960
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of α-fluoromethylhistidine-evoked histamine depletion on ultrastructure of endocrine cells in acid-producing mucosa of stomach in mouse, rat and hamster (1996)
    Springer
    Cell & tissue research 286 (1996), S. 375-384 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Endocrine cells ; Stomach-ECL cells ; Ultrastructure ; Histamine ; α-Fluoromethylhistidine ; Secretory vesicles ; Rat (Sprague Dawley) ; Mouse (NMRI) ; Hamster (Syrian)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The oxyntic mucosa of the mammalian stomach is rich in endocrine cells, such as ECL cells, A-like cells, somatostatin cells, D1/P cells and, in some species, enterochromaffin cells. The various endocrine cell types can be distinguished on the basis of their characteristic cytoplasmic granules and vesicles. The ECL cells contain numerous large secretory vesicles and relatively few, small electron-dense granules and small clear microvesicles. We have suggested that in the rat the ECL cells contain most of the gastric histamine with the secretory vesicles as the major histamine storage site in these cells. α-Fluoromethylhistidine is an irreversible inhibitor of histidine decarboxylase, the histamine-forming enzyme. We have previously shown that this enzyme inhibitor depletes histamine from the ECL cells in the rat and reduces the number of secretory vesicles in the cytoplasm. In the present study, we have examined whether α-fluoromethylhistidine affects the ECL cells in other species and whether it affects other types of endocrine cells in the oxyntic mucosa of the rat. Mice, rats and hamsters were treated with the inhibitor (3 mg/kg per h) via minipumps subcutaneously for 24 h. This treatment lowered the oxyntic mucosal histamine concentration by 65–90% and the number and volume density of the secretory vesicles by 85–95% in the ECL cells of the three species examined. In contrast, the number and volume density of granules and microvesicles were not greatly affected. No evidence was found for an effect of α-fluoromethylhistidine on A-like cells, somatostatin cells or D1/P cells of the rat stomach, suggesting that, unlike the ECL cells, they do not contain histamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050707
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  • 5
    Electronic Resource
    Electronic Resource
    Time course of hypertrophic and ultrastructural responses of rat stomach enterochromaffin-like cells to sustained hypergastrinemia (1996)
    Springer
    Cell & tissue research 284 (1996), S. 55-63 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Enterochromaffin-like (ECL) cells ; Gastrin ; Granules/vesicles ; Hypertrophy ; Ultrastructure ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Previously, we have investigated the effects of short-term (minutes to hours) and long-term (weeks to months) stimulation with gastrin on the histamine-producing enterochromaffin-like (ECL) cells in the oxyntic mucosa of rat stomach. The present study examines the response of the ECL cells of freely fed rats to sustained hypergastrinemia over a time span of a few hours to four weeks. Sustained hypergastrinemia was induced by the continuous subcutaneous infusion of human Leu15-gastrin-17. The histidine decarboxylase (HDC) activity and histamine concentration in the oxyntic mucosa were monitored throughout the study. ECL cell profiles in electron micrographs were analysed planimetrically. The HDC activity displayed a 4-fold increase within the first two days. Subsequently, it remained at a plateau. The histamine concentration increased 2- to 3-fold in response to gastrin. The rise in histamine was slower than the rise in HDC activity. At no time point was there a reduced concentration of histamine. The ECL cells increased in size after 4 days of hypergastrinemia, reaching a maximum cell profile area after 2 weeks and remaining enlarged for the duration of the study. The secretory vesicles were reduced in number after 1 day, returning gradually to the pre-stimulation value thereafter; their volume density remained reduced during the 6-day observation period. Vacuoles started to appear after 1 day of hypergastrinemia and their number and volume density increased, reaching a maximum after 4 days. The number and volume density of the microvesicles increased and plateaued after 2 days of hypergastrinemia. The number of granules per cell profile was unaffected but their volume density was greatly reduced after 4 days of hypergastrinemia (reflecting the ECL cell hypertrophy). The present findings establish the time course of activation of the ECL cells in response to sustained hypergastrinemia over a time span of a few hours to four weeks; a new ”steady state” situation at a high level of activity has been established after about a week.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050566
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  • 6
    Electronic Resource
    Electronic Resource
    Secretory organelles in ECL cells of the rat stomach: an immunohistochemical and electron-microscopic study (1999)
    Springer
    Cell & tissue research 298 (1999), S. 457-470 
    Details
    ISSN: 1432-0878
    Keywords: Confocal microscopy Gastrin Histamine Morphometry Pancreastatin Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. ECL cells are numerous in the rat stomach. They produce and store histamine and chromogranin-A (CGA)-derived peptides such as pancreastatin and respond to gastrin with secretion of these products. Numerous electron-lucent vesicles of varying size and a few small, dense-cored granules are found in the cytoplasm. Using confocal and electron microscopy, we examined these organelles and their metamorphosis as they underwent intracellular transport from the Golgi area to the cell periphery. ECL-cell histamine was found to occur in both cytosol and secretory vesicles. Histidine decarboxylase, the histamine-forming enzyme, was in the cytosol, while pancreastatin (and possibly other peptide products) was confined to the dense cores of granules and secretory vesicles. Dense-cored granules and small, clear microvesicles were more numerous in the Golgi area than in the docking zone, i.e. close to the plasma membrane. Secretory vesicles were numerous in both Golgi area and docking zone, where they were sometimes seen to be attached to the plasma membrane. Upon acute gastrin stimulation, histamine was mobilized and the compartment size (volume density) of secretory vesicles in the docking zone was decreased, while the compartment size of microvesicles was increased. Based on these findings, we propose the following life cycle of secretory organelles in ECL cells: small, electron-lucent microvesicles (pro-granules) bud off the trans Golgi network, carrying proteins and secretory peptide precursors (such as CGA and an anticipated prohormone). They are transformed into dense-cored granules (approximate profile diameter 100 nm) while still in the trans Golgi area. Pro-granules and granules accumulate histamine, which leads to their metamorphosis into dense-cored secretory vesicles. In the Golgi area the secretory vesicles have an approximate profile diameter of 150 nm. By the time they reach their destination in the docking zone, their profile diameter is between 200 and 500 nm. Exocytosis is coupled with endocytosis (membrane retrieval), and microvesicles in the docking zone are likely to represent membrane retrieval vesicles (endocytotic vesicles).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004419900075
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of reserpine on ECL-cell ultrastructure and histamine compartmentalization in the rat stomach (1999)
    Springer
    Cell & tissue research 295 (1999), S. 131-140 
    Details
    ISSN: 1432-0878
    Keywords: Key words ECL cells ; Gastrin ; Reserpine ; Organelles ; Ultrastructure ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The histamine-storing ECL cells in the stomach play a key role in the control of acid secretion. They contain granules, secretory vesicles and microvesicles, and sustained gastrin stimulation results in the additional formation of vacuoles and lipofuscin bodies. The cells are rich in the vesicle monoamine transporter type-2 (VMAT-2), which can be inhibited by reserpine. The present study examines the effect of reserpine on ECL-cell ultrastructure and histamine compartmentalization. Rats received reserpine and/or gastrin. Reserpine was given twice by the intraperitoneal route (25 mg/kg once daily). Gastrin-17 was given by subcutaneous infusion (5 nmol/kg/h), starting at the time of the first reserpine injection and continuing for 4 days when the rats were killed. At this stage, histamine in the oxyntic mucosa was unaffected by reserpine but elevated by gastrin. Immunocytochemical analysis (confocal microscopy) showed ECL-cell histamine in control and gastrin-treated rats to be localized in cytoplasmic organelles (e.g., secretory vesicles). After treatment with reserpine alone or reserpine+gastrin, ECL-cell histamine occurred mainly in the cytosol. Planimetric analysis (electron microscopy) of ECL cells showed reserpine to increase the number, size and volume density of the granules and to reduce the size and volume density of the secretory vesicles. Gastrin reduced the number and volume density of granules and secretory vesicles, increased the number and volume density of microvesicles and caused vacuoles and lipofuscin bodies to appear. Reserpine+gastrin increased the number, volume density and size of the granules. Reserpine prevented the effects of gastrin on secretory vesicles, vacuoles and microvesicles, but did not prevent the development of lipofuscin. Our findings are in line with the views: (1) that preformed cytosolic histamine is taken up by granules/secretory vesicles via VMAT-2, that histamine is instrumental in the transformation of granules into secretory vesicles and in their consequent enlargement and (2) that vacuoles are formed by the fusion of large secretory vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051219
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