Control of acid secretion in cultured gas gland cells of the European eel Anguilla anguilla

1996 ◽  
Vol 270 (3) ◽  
pp. R578-R584
Author(s):  
B. Pelster ◽  
L. Pott

Single cells and cell clusters isolated from the swimbladder epithelium of the European eel Anguilla anguilla attached to collagen S-coated petri dishes and proliferated in a modified Dulbecco's modified Eagle's medium, supplemented with 0.5% fetal calf serum. At a temperature of 20-22 degrees C, the growing colonies reached confluence typically within 6-8 days. Activities of glycolytic and pentose phosphate shunt enzymes remained stable or increased only slightly during the first 10 days of primary culture. Incubated in a defined medium providing glucose as a fuel, gas gland cells in primary culture produced and released lactic acid. The rate of acid secretion of cultured gas gland cells measured with a cytosensor microphysiometer was not influenced by cholinergic stimulation. Similarly, the Ca2+ ionophore A-23187 had no effect. Adrenergic stimulation with epinephrine or the beta-agonist isoproterenol also did not increase the rate of acid secretion, indicating that in gas gland cells the metabolic activity cannot be stimulated via beta-adrenergic stimulation followed by an increase in adenosine 3',5'-cyclic monophosphate (cAMP). Artificially increasing the intracellular concentration of cAMP by incubation with forskolin or the cAMP analogue 8-(4-chlorophenylthio)-cAMP even resulted in a marked reduction in the rate of acid secretion. The results demonstrate that primary cell culture provides a useful means for the analysis of metabolic control and of ion transfer processes in swimbladder gas gland cells.

Parasitology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Bahram Sayyaf Dezfuli ◽  
Chiara Maestri ◽  
Massimo Lorenzoni ◽  
Antonella Carosi ◽  
Barbara J Maynard ◽  
...  

Abstract The swimbladder functions as a hydrostatic organ in most bony fishes, including the European eel, Anguilla anguilla. Infection by the nematode Anguillicoloides crassus impairs swimbladder function, significantly compromising the success of the eel spawning migration. Swimbladders from 32 yellow eels taken from Lake Trasimeno (Central Italy) were analysed by histopathology- and electron microscopy-based techniques. Sixteen eels (50%) harboured A. crassus in their swimbladders and intensity of infection ranged from 2 to 17 adult nematodes per organ (6.9 ± 1.6, mean ± s.e.). Gross observations of heavily infected swimbladders showed opacity and histological analysis found a papillose aspect to the mucosa and hyperplasia of the lamina propria, muscularis mucosae and submucosa. Inflammation, haemorrhages, dilation of blood vessels and epithelial erosion were common in infected swimbladders. In the epithelium of parasitized swimbladders, many empty spaces and lack of apical junctional complexes were frequent among the gas gland cells. In heavily infected swimbladders, we observed hyperplasia, cellular swelling and abundant vacuolization in the apical portion of the gas gland cells. Numerous mast cells and several macrophage aggregates were noticed in the mucosal layer of infected swimbladders. We found more nervous and endocrine elements immunoreactive to a panel of six rabbit polyclonal antibodies in infected swimbladders compared to uninfected.


2002 ◽  
Vol 205 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
E. Sötz ◽  
H. Niederstätter ◽  
B. Pelster

SUMMARY Gas gland cells of the European eel (Anguilla anguilla) were cultured on collagen-coated coverslips, and intracellular pH was measured using the pH-sensitive fluorescent probe 2′,7′-bis-(2-carboxypropyl)-5-(6)-carboxyfluorescein (BCPCF). The contributions of various proton-translocating mechanisms to homeostasis of intracellular pH (pHi) were assessed by adding specific inhibitors of the various proton-translocating mechanisms at a constant extracellular pH (pHe)of 7.4 and after artificial acidification of the cells using the ammonium pulse technique. The greatest decrease in pHi was observed after addition of 5-(N-ethyl-N-isobutyl)-amiloride (MIA), an inhibitor of Na+/H+ exchange. Na+/H+ exchange was active under steady-state conditions at an extracellular pH of 7.4, and activity increased after intracellular acidification. Incubation of gas gland cells with 4,4′-diisothiocyanostilbene-2,2′-disulphonic acid(DIDS), an inhibitor of anion exchange, also caused a decrease in pHi, but this decrease was not as pronounced as in the presence of MIA. Furthermore, at low pHi, the effect of DIDS was further reduced, suggesting that bicarbonate-exchanging mechanisms are involved in maintaining a steady-state pHi but that their importance is reduced at low pH. Bafilomycin A1,a specific inhibitor of the V-ATPase, had no effect on steady-state pHi. However, recovery of intracellular pH after an artificial acid load was significantly impaired in the presence of bafilomycin. Our results suggest that Na+/H+ exchange and anion exchange are important for the regulation of pHi at alkaline values of pHe. When pHi is low, a situation probably often encountered by gas gland cells during gas secretion,Na+/H+ exchange continues to play an important role in acid secretion and a V-ATPase appears to contribute to proton secretion.


1995 ◽  
Vol 269 (4) ◽  
pp. R793-R799 ◽  
Author(s):  
B. Pelster

Mechanisms of acid production and of acid release have been analyzed in isolated gas gland cells of the eel swimbladder using a cytosensor microphysiometer. Incubation of isolated cells with oxamic acid caused a dose-dependent decrease in the rate of proton release. At the highest oxamic acid concentration used (20 mmol/l), proton release was reduced by approximately 40%; incubation with sodium fluoride (10 mmol/l) or removal of glucose from the extracellular medium caused 60 and 80% reduction, respectively. NaCN had little effect on proton secretion. Proton release of isolated gas gland cells was largely dependent on the extracellular sodium concentration, and this sodium effect was in part inhibitable by amiloride. A 15-20% reduction in the rate of proton secretion was observed in the presence of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, an inhibitor of anion exchange. Inhibition of mammalian H(+)-K(+)-adenosinetriphosphatase with omeprazole had no effect, whereas bafilomycin, an inhibitor of vesicular H(+)-adenosinetriphosphatase, induced a 25% reduction in proton secretion. Ethoxzolamide, a membrane-permeable inhibitor of carbonic anhydrase, caused a 60% reduction in proton secretion (inhibition constant = 54.4 nmol/l). Prontosil-dextran, a membrane-impermeable sulfonamide, also reduced the proton release, thus indicating the presence of a membrane-bound carbonic anhydrase facing the extracellular space.


PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0239627
Author(s):  
Gabriel Schneebauer ◽  
Constantin Lindemann ◽  
Victoria Drechsel ◽  
Lasse Marohn ◽  
Klaus Wysujack ◽  
...  

2000 ◽  
Vol 279 (6) ◽  
pp. R2336-R2343 ◽  
Author(s):  
C. Prem ◽  
W. Salvenmoser ◽  
J. Würtz ◽  
B. Pelster

Electron microscopical examination of gas gland cells of the physostome European eel ( Anguilla anguilla) and of the physoclist perch ( Perca fluviatilis) revealed the presence of significant numbers of lamellar bodies, which are known to be involved in surfactant secretion. In the perch, in which the gas gland is a compact structure and gas gland cells are connected to the swim bladder lumen via small canals, lamellar bodies were also found in flattened cells forming the swim bladder epithelium. Flat epithelial cells are absent in the eel swim bladder, in which the whole epithelium consists of cuboidal gas gland cells. In both species, Western blot analysis using specific antibodies to human surfactant protein A (SP-A) showed a cross-reaction with swim bladder tissue homogenate proteins of ∼65 kDa and in the eel occasionally of ∼120 kDa, probably representing SP-A-like proteins in a dimeric and a tetrameric state. An additional band was observed at ∼45 kDa. Western blots using antibodies to rat SP-D again resulted in a single band at ∼45 kDa in both species, suggesting that there might be a cross-reaction of the antibody to human SP-A with an SP-D-like protein of the swim bladder tissue. To localize the surfactant protein, eel gas gland cells were cultured on permeable supports. Under these conditions, the gas gland cells regain their characteristic polarity. Electron microscopy confirmed the presence of lamellar bodies in cultured cells, and occasionally, exocytotic events were observed. Immunohistochemical staining using an antibody to human SP-A demonstrated the presence of surfactant protein only in luminal membranes and in adjacent lateral membranes. Only occasionally, evidence was found for the presence of surfactant protein in lamellar bodies.


2001 ◽  
Vol 204 (23) ◽  
pp. 4023-4029
Author(s):  
Caroline Prem ◽  
Bernd Pelster

SUMMARY A cell culture system has been developed in which swimbladder gas gland cells from the European eel (Anguilla anguilla) were cultured on a permeable support. Cells seeded on Anodisc 13 (Whatman) or Costar Transwell 13 mm membranes form a confluent cell layer within the first 2 or 3 days of culture but, on the basis of measurements of transepithelial resistance, it is a ‘leaky’ cell layer. In a superfusion system, the apical and basal sides of the cells were superfused asymmetrically, with saline on the apical side and a glucose-containing cell culture medium on the basal side. Under these conditions, the cells continuously produced lactic acid, and approximately 60–70 % of this lactate was released at the basal side. To mimic the in vivo situation, the saline solution supplied to the apical side was replaced by humidified air in an additional series of experiments. Cells cultured in an air/liquid system produced even more lactate, and this lactate was only released to the basal side; there was no leakage of fluid to the apical side. After 4 or 5 days in the superfusion system, the cells were fixed for histological examination. The cells were columnar, similar to gas gland cells in vivo, and showed a clear polarity, with some small microvilli at the apical membrane and extensive membrane foldings at lateral and basal membranes. Immunohistochemical localization of Na+/K+-ATPase revealed that this ATPase was present mainly in the lateral membranes; it was never found in the apical membranes. Cells cultured in the air/liquid system showed a similar structure and polarity.


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