scholarly journals Metabolism of the Perfused Swtmbladder of the European EEL: Oxygen, Carbon Dioxide, Glucose and Lactate Balance

1989 ◽  
Vol 144 (1) ◽  
pp. 495-506 ◽  
Author(s):  
B. PELSTER ◽  
H. KOBAYASHI ◽  
P. SCHEID
Keyword(s):  
Lactate Production ◽  
Anguilla Anguilla ◽  
Co2 Production ◽  
European Eel ◽  
Fick Principle ◽  
Partial Pressures ◽  
Gland Tissue ◽  
Arterial Inflow ◽  
Co2 Washout ◽  
Gas Gland

We have measured the metabolic activity in the vascularly isolated, salineperfused swimbladder of the eel (Anguilla anguilla) in order to investigate the pathways for CO2 formation in the gas gland tissue. Concentrations of O2, CO2, glucose and lactate were measured in the arterial inflow and venous outflow of the swimbladder, and metabolic rates were calculated by the direct Fick principle. 1. Total CO2 production, averaging 55.8nmol min−1, was about 4.6 times the O2 consumption (mean 12.0nmol min−1). This suggests that only about 22% of the CO2 is formed by aerobic glucose metabolism. 2. CO2 formation from HCO3− or CO2 washout does not appear to be significant in our experiments with steady perfusion of a saline containing a low level of HCO3−. 3. The ratio of lactate production to glucose uptake averaged 1.2, indicating that only 60% of the glucose is converted to lactate. Since only 1–2% of the glucose was found to be oxidized (2 nmol min−1), the extra glucose appears to be anoxidatively metabolized to CO2. 4. The anoxidative CO2 formation appears to be of functional importance for producing the high gas partial pressures of both CO2 and O2 which are required for secretion of these gases into the swimbladder.

scholarly journals GLUCOSE METABOLISM OF THE SWIMBLADDER TISSUE OF THE EUROPEAN EEL ANGUILLA ANGUILLA

1993 ◽  
Vol 185 (1) ◽  
pp. 169-178 ◽  
Author(s):  
B. Pelster ◽  
P. Scheid
Keyword(s):  
Glucose Uptake ◽  
Venous Blood ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Anguilla Anguilla ◽  
Pentose Phosphate ◽  
Co2 Production ◽  
European Eel ◽  
O2 Uptake ◽  
Lactate Release

Glucose uptake from, and lactate release into, the blood have been analysed in the active gas- depositing swimbladder of the immobilized European eel Anguilla anguilla. Under normoxic conditions, 0.72 micromole min-1 glucose was removed from the blood supply, while lactate was released into it at a rate of 1.16 micromole min-1. The rate of gas deposition into the swimbladder was significantly correlated with the rate of lactate production. Under hypoxic conditions, glucose consumption by, and lactate production of, the swimbladder tissue were reduced, as was the rate of gas deposition. Compared with normoxic conditions, lactate concentration in the swimbladder tissue was elevated after 1 h of hypoxia, indicating a decrease in lactate release. No difference in the osmolality of arterial and venous blood could be detected in these experiments. Combining the data for glucose uptake and lactate release measured under normoxic conditions with the values for O2 uptake and CO2 production of the swimbladder tissue measured under similar conditions in a previous study, a quantitative evaluation of glucose catabolism was performed. According to the O2 uptake of the tissue, only about 1 % of the glucose was oxidized, while about 80 % was fermented to lactic acid. The remaining 0.14 micromole min-1 glucose was presumably catabolized through the pentose phosphate shunt, as indicated by the CO2 production of 0.16 micromole min-1 that cannot be explained by aerobic metabolism.

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.

scholarly journals Vasodilation of swimbladder vessels in the european eel (Anguilla anguilla) induced by vasoactive intestinal polypeptide, nitric oxide, adenosine and protons

1999 ◽  
Vol 202 (8) ◽  
pp. 1005-1013
Author(s):  
T. Schwerte ◽  
S. Holmgren ◽  
B. Pelster
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Vasoactive Intestinal Polypeptide ◽  
Gland Cell ◽  
Perfusion Pressure ◽  
Cell Metabolism ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Gas Gland ◽  
Intestinal Polypeptide

The effects of β-adrenergic stimulation, vasoactive intestinal polypeptide (VIP), adenosine, the nitric oxide (NO)-releasing agent sodium nitroprusside and of metabolic end-products of gas gland cell metabolism on swimbladder blood flow were investigated using saline- or blood-perfused swimbladder preparations of the freshwater European eel Anguilla anguilla. While β-adrenergic vasodilation was not detectable, a bolus injection of adenosine (100 microl, 10(−)7 mol l-1) and application of VIP (10(−)7 mol kg-1) caused a significant decrease in perfusion pressure in saline-perfused swimbladder preparations. Immunohistochemical analysis revealed the presence of VIP-immunoreactive nerve fibres in the swimbladder artery and in the swimbladder vein (seawater-adapted eels were used for immunohistochemical studies). Application of sodium nitroprusside also elicited a small, but significant, decrease in perfusion pressure in saline-perfused swimbladder preparations, while preincubation of swimbladder tissue with N(ω)nitro-l-arginine, a non-selective inhibitor of nitric oxide synthase, significantly enhanced the flow-induced increase in perfusion pressure. Lactate, the major metabolic end-product of gas gland cell metabolism, had no effect on perfusion pressure. In contrast, an increase in proton concentration in both saline- and blood-perfused preparations induced a vasodilation, as indicated by a significant decrease in perfusion pressure. The results demonstrate that VIP, NO, adenosine and protons may induce a vasodilation of swimbladder blood vessels. None of these effects, however, compares in time span with the previously described immediate, short-lasting vasodilation of swimbladder vessels elicited by pulse stimulation of the vagus nerve.

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.

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.

scholarly journals THE INFLUENCE OF GAS GLAND METABOLISM AND BLOOD FLOW ON GAS DEPOSITION INTO THE SWIMBLADDER OF THE EUROPEAN EEL ANGUILLA ANGUILLA

1992 ◽  
Vol 173 (1) ◽  
pp. 205-216 ◽  
Author(s):  
B. Pelster ◽  
P. Scheid
Keyword(s):  
Blood Flow ◽  
Metabolic Activity ◽  
Venous Blood ◽  
Blood Perfusion ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Hypoxic Conditions ◽  
Arterial Blood ◽  
Flow Through ◽  
Gas Gland

The effects of blood flow through, and metabolic activity in, the swimbladder epithelium on gas deposition into the swimbladder have been analysed in the European eel, Anguilla anguilla. Blood flow in the artery supplying the retia was measured by Doppler flow probes; measurement of O2 and CO2 content in arterial and venous blood samples from the swimbladder allowed calculation of the rates of O2 removal from, and CO2 addition to, swimbladder blood. 83 % of the O2 removed from the blood was transferred into the swimbladder lumen and only 17 % was metabolized in the tissue. In spite of the deposition of CO2 into the swimbladder lumen, the CO2 content in rete venous blood was higher than that in arterial blood, indicating production of CO2 in the swimbladder tissue. The respiratory exchange ratio, calculated from O2 consumption and CO2 production of the swimbladder tissue, was significantly greater than one. Gas deposition into the swimbladder increased with increasing swimbladder arteriovenous pH difference, indicating acid release from gas gland cells, and thus their metabolic activity. The rate of gas deposition into the swimbladder increased with increasing blood perfusion of the swimbladder tissue. Under hypoxic conditions, gas deposition was significantly reduced, as was blood flow through the swimbladder tissue. The decrease in gas deposition during hypoxia coincided with a reduction in the swimbladder arteriovenous pH difference. The results therefore demonstrate that the rate of gas deposition is dependent on blood perfusion of the swimbladder tissue and on metabolic activity of the swimbladder tissue, both of which are reduced under hypoxic conditions.

scholarly journals Expression of transport proteins in the rete mirabile of european silver and yellow eel

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gabriel Schneebauer ◽  
Victoria Drechsel ◽  
Ron Dirks ◽  
Klaus Faserl ◽  
Bettina Sarg ◽  
...  
Keyword(s):  
Transport Proteins ◽  
European Eel ◽  
Back Diffusion ◽  
Root Effect ◽  
Rete Mirabile ◽  
Partial Pressures ◽  
Silver Eels ◽  
Ion Channel Proteins ◽  
Gas Molecules ◽  
Gas Gland

Abstract Background In physoclist fishes filling of the swimbladder requires acid secretion of gas gland cells to switch on the Root effect and subsequent countercurrent concentration of the initial gas partial pressure increase by back-diffusion of gas molecules in the rete mirabile. It is generally assumed that the rete mirabile functions as a passive exchanger, but a detailed analysis of lactate and water movements in the rete mirabile of the eel revealed that lactate is diffusing back in the rete. In the present study we therefore test the hypothesis that expression of transport proteins in rete capillaries allows for back-diffusion of ions and metabolites, which would support the countercurrent concentrating capacity of the rete mirabile. It is also assumed that in silver eels, the migratory stage of the eel, the expression of transport proteins would be enhanced. Results Analysis of the transcriptome and of the proteome of rete mirabile tissue of the European eel revealed the expression of a large number of membrane ion and metabolite transport proteins, including monocarboxylate and glucose transport proteins. In addition, ion channel proteins, Ca2+-ATPase, Na+/K+-ATPase and also F1F0-ATP synthase were detected. In contrast to our expectation in silver eels the expression of these transport proteins was not elevated as compared to yellow eels. A remarkable number of enzymes degrading reactive oxygen species (ROS) was detected in rete capillaries. Conclusions Our results reveal the expression of a large number of transport proteins in rete capillaries, so that the back diffusion of ions and metabolites, in particular lactate, may significantly enhance the countercurrent concentrating ability of the rete. Metabolic pathways allowing for aerobic generation of ATP supporting secondary active transport mechanisms are established. Rete tissue appears to be equipped with a high ROS defense capacity, preventing damage of the tissue due to the high oxygen partial pressures generated in the countercurrent system.

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