Determinants of intracellular pH in gas gland cells of the swimbladder of the European eel Anguilla anguilla

2002 ◽  
Vol 205 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
E. Sötz ◽  
H. Niederstätter ◽  
B. Pelster
Keyword(s):  
Steady State ◽  
Anion Exchange ◽  
Intracellular Ph ◽  
Specific Inhibitor ◽  
Anguilla Anguilla ◽  
Extracellular Ph ◽  
European Eel ◽  
Pulse Technique ◽  
Gland Cells ◽  
Gas Gland

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.

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
Keyword(s):  
Acid Secretion ◽  
Primary Culture ◽  
Single Cells ◽  
Calf Serum ◽  
Anguilla Anguilla ◽  
Beta Agonist ◽  
European Eel ◽  
Adrenergic Stimulation ◽  
Gland Cells ◽  
Gas Gland

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.

Na+/H+ exchange in mosquito Malpighian tubules

2000 ◽  
Vol 279 (6) ◽  
pp. R1996-R2003 ◽  
Author(s):  
D. H. Petzel
Keyword(s):  
Steady State ◽  
Intracellular Ph ◽  
Specific Inhibitor ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Pulse Technique ◽  
Acid Load ◽  
Rate Of Recovery ◽  
Stimulation Of

Fluid secretion and intracellular pH were measured in isolated mosquito Malpighian tubules to determine the presence of Na+/H+ exchange. Rates of fluid secretion by individual Malpighian tubules in vitro were inhibited by 78% of control in the presence of 100 μM 5-( N-ethyl- n-isopropyl)-amiloride (EIPA), a specific inhibitor of Na+/H+ exchange. Steady-state intracellular pH was measured microfluorometrically by using 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein in individual Malpighian tubules. Bathing the Malpighian tubules in 0 mM extracellular Na+ or in the presence of 100 μM EIPA reduced the steady-state intracellular pH by 0.5 pH units. Stimulation of the Na+/H+ exchanger by using the NH4Cl pulse technique resulted in a rate of recovery from the NH4Cl-induced acute acid load of 8.7 ± 1.0 × 10−3 pH/s. The rates of recovery of intracellular pH after the acute acid load in the absence of extracellular Na+ or in the presence of 100 μM EIPA were 0.7 ± 0.6 and −0.3 ± 0.3 × 10−3 pH/s, respectively. These results indicate that mosquito Malpighian tubules possess a Na+/H+ exchanger.

The impact of Anguillicoloides crassus (Nematoda) on European eel swimbladder: histopathology and relationship between neuroendocrine and immune cells

Parasitology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Bahram Sayyaf Dezfuli ◽  
Chiara Maestri ◽  
Massimo Lorenzoni ◽  
Antonella Carosi ◽  
Barbara J Maynard ◽  
...  
Keyword(s):  
Polyclonal Antibodies ◽  
Central Italy ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Gland Cells ◽  
Bony Fishes ◽  
Mucosal Layer ◽  
Gas Gland ◽  
The Impact ◽  
Anguillicoloides Crassus

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.

Adaptation to hypercapnia vs. intracellular pH in cat carotid body: responses in vitro

1996 ◽  
Vol 80 (4) ◽  
pp. 1090-1099 ◽  
Author(s):  
S. Lahiri ◽  
R. Iturriaga ◽  
A. Mokashi ◽  
F. Botre ◽  
D. Chugh ◽  
...  
Keyword(s):  
Steady State ◽  
Intracellular Ph ◽  
Baseline Level ◽  
Discharge Rate ◽  
Initial Response ◽  
Extracellular Ph ◽  
Carotid Bodies ◽  
Initial Peak ◽  
Initial Change

The hypotheses that the chemosensory discharge rate parallels the intracellular pH (pHi) during hypercapnia and that the initial change in pHi (delta pHi) is always more than the stead-state delta pHi were studied by using cat carotid bodies in vitro at 36.5 degrees C in the absence and presence of methazolamide (30-100 mg/l). Incremental acidic hypercapnia was followed by an incremental initial peak response and a greater adaptation. A given acidic hypercapnia elicited a rapid initial response followed by a slower adaptation; isohydric hypercapnia produced an equally rapid initial response but of smaller magnitude that returned to near-baseline level; alkaline hypercapnia induced a similar rapid initial response but one of still smaller magnitude that decreased rapidly to below the baseline. Methazolamide eliminated the initial overshoot, which also suggested involvement of the initial rapid pHi in the overshoot. These results show that the initial delta pHi is always greater than the steady-state delta pHi and during hypercapnia. Also, the steady-state chemoreceptor activity varied linearly with the extracellular pH, indicating a linear relationship between extracellular pH and pHi.

Mechanisms of acid release in isolated gas gland cells of the European eel Anguilla anguilla

1995 ◽  
Vol 269 (4) ◽  
pp. R793-R799 ◽  
Author(s):  
B. Pelster
Keyword(s):  
Carbonic Anhydrase ◽  
Disulfonic Acid ◽  
European Eel ◽  
Proton Release ◽  
Isolated Cells ◽  
Extracellular Medium ◽  
Proton Secretion ◽  
Gland Cells ◽  
Acid Release ◽  
Gas Gland

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.

scholarly journals Swimming under elevated hydrostatic pressure increases glycolytic activity in gas gland cells of the European eel

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0239627
Author(s):  
Gabriel Schneebauer ◽  
Constantin Lindemann ◽  
Victoria Drechsel ◽  
Lasse Marohn ◽  
Klaus Wysujack ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
European Eel ◽  
Gland Cells ◽  
Elevated Hydrostatic Pressure ◽  
Glycolytic Activity ◽  
Gas Gland

scholarly journals Intracellular pH of giant salivary gland cells of the leech Haementeria ghilianii: regulation and effects on secretion.

1994 ◽  
Vol 189 (1) ◽  
pp. 179-198
Author(s):  
W A Wuttke ◽  
T Munsch ◽  
M S Berry
Keyword(s):  
Salivary Gland ◽  
Intracellular Ph ◽  
Salivary Secretion ◽  
Proton Pumping ◽  
Pulse Technique ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Acid Load ◽  
Dependent Transport ◽  
Acid Loading

1. Intracellular pH (pHi) and membrane potential (Em) of giant salivary gland cells of the leech, Haementeria ghilianii, were measured with double-barrelled, neutral-carrier, pH-sensitive microelectrodes. 2. Em was -51 +/- 11.2 mV and pHi was 6.98 +/- 0.1 (mean +/- S.D., N = 41) in Hepes-buffered saline (nominally HCO3(-)-free; extracellular pH, pHe = 7.4). pHi was independent of Em. 3. Amiloride (2 mmol l-1) had no effect on resting pHi or on pHi recovery from an acid load (induced by the NH4+ pre-pulse technique). Removal of external Na+ produced a progressive acidification which was blocked by amiloride, and the drug also slowed the recovery of pHi on reintroduction of Na+. The results indicate the presence of an electroneutral Na+/H+ exchanger whose access to amiloride is competitively blocked by Na+. 4. In certain smaller cells of the gland, which probably form a separate population, removal of external Na+ did not affect pHi, and recovery from an acid load was blocked by amiloride. There may, therefore, be two types of Na+/H+ exchanger, differing in reversibility and sensitivity to amiloride. 5. Recovery of pHi from NH4(+)-induced acid loading was not affected by bicarbonate-buffered saline (2% CO2; 11 mmol l-1 HCO3-) or by addition of the anion-exchange blocker SITS (10(-4) mol l-1). This suggests that there is no significant contribution of a HCO3(-)-dependent transport mechanism to pHi regulation in the gland cells. 6. Removal of external Cl- slowly reduced pHi and there was a transient increase (overshoot) in pHi when Cl- was reintroduced. These effects of Cl- are probably explained by changes in the Na+ gradient. Intracellular Na+ and Cl- activities were measured with ion-selective microelectrodes. 7. Acidification with NH4+ was difficult, probably because of the cells' poor permeability to this ion. Attempts to introduce NH4+ via the Na+ pump or Na+/Cl- transporter were not successful. The H+/K+ ionophore nigericin (1 microgram ml-1), however, produced a rapid and reversible acidification. 8. N-methylmaleimide (0.5-1 mmol l-1), which blocks proton-pumping ATPase, produced a prolonged acidification of almost 1 pH unit, well beyond the level expected for simple equilibration with pHe. The results are consistent with the presence of a vesicular proton pump, acidifying the secretory vesicles which pack the cell body. 9. NH4+ (50 mmol l-1) or trimethylamine (50 mmol l-1) increased pHi and stimulated salivary secretion, while propionate (50 mmol l-1) decreased pHi and stopped secretion.(ABSTRACT TRUNCATED AT 400 WORDS)

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