scholarly journals Tissue and salinity specific Na+/Cl− cotransporter (NCC) orthologues involved in the adaptive osmoregulation of sea lamprey (Petromyzon marinus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Barany ◽  
C. A. Shaughnessy ◽  
R. M. Pelis ◽  
J. Fuentes ◽  
J. M. Mancera ◽  
...  
Keyword(s):  
Water Absorption ◽  
Salinity Tolerance ◽  
Ex Vivo ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Sea Lamprey ◽  
Mrna Levels ◽  
Gene Encoding ◽  
Distal Intestine ◽  
Proximal Intestine

AbstractTwo orthologues of the gene encoding the Na+-Cl− cotransporter (NCC), termed ncca and nccb, were found in the sea lamprey genome. No gene encoding the Na+-K+-2Cl− cotransporter 2 (nkcc2) was identified. In a phylogenetic comparison among other vertebrate NCC and NKCC sequences, the sea lamprey NCCs occupied basal positions within the NCC clades. In freshwater, ncca mRNA was found only in the gill and nccb only in the intestine, whereas both were found in the kidney. Intestinal nccb mRNA levels increased during late metamorphosis coincident with salinity tolerance. Acclimation to seawater increased nccb mRNA levels in the intestine and kidney. Electrophysiological analysis of intestinal tissue ex vivo showed this tissue was anion absorptive. After seawater acclimation, the proximal intestine became less anion absorptive, whereas the distal intestine remained unchanged. Luminal application of indapamide (an NCC inhibitor) resulted in 73% and 30% inhibition of short-circuit current (Isc) in the proximal and distal intestine, respectively. Luminal application of bumetanide (an NKCC inhibitor) did not affect intestinal Isc. Indapamide also inhibited intestinal water absorption. Our results indicate that NCCb is likely the key ion cotransport protein for ion uptake by the lamprey intestine that facilitates water absorption in seawater. As such, the preparatory increases in intestinal nccb mRNA levels during metamorphosis of sea lamprey are likely critical to development of whole animal salinity tolerance.

Tissue- and Salinity-specific Na–Cl Cotransporter (NCC) Orthologues Involved in the Sea lamprey (Petromyzon Marinus) Adaptive Osmoregulation

2021 ◽  
Author(s):  
A. Barany ◽  
C. A. Shaughnessy ◽  
R. M. Pelis ◽  
J. Fuentes ◽  
J. M. Mancera ◽  
...  
Keyword(s):  
Water Absorption ◽  
Ex Vivo ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Petromyzon Marinus ◽  
Short Circuit Current ◽  
Sea Lamprey ◽  
Intestinal Tissue ◽  
Distal Intestine ◽  
Phylogenetic Comparison

Abstract Two ncc orthologues (termed ncca and nccb) were found in the sea lamprey genome, whereas nkcc2 was not. In a phylogenetic comparison among other vertebrate amino acids, NCC and NKCC deduced sequences, the sea lamprey NCC’s occupied basal positions within the NCC clade. In freshwater, ncca mRNA was found only in the gill and nccb only in the intestine, whereas both were found in the kidney. Acclimation to seawater increased nccb mRNA in the intestine and kidney. Intestinal nccb mRNA also increased during late metamorphosis. The electrophysiological approach in the Ussing chamber of intestinal tissue ex vivo showed significant differences between freshwater and seawater-acclimated juveniles. Luminal application of indapamide (NCC inhibitor) resulted in 73 and 30% inhibition of short-circuit current (Isc) in the proximal and distal intestine, respectively. The luminal application of bumetanide (NKCC inhibitor) did not affect intestinal Isc. Indapamide also inhibited ex vivo intestinal water absorption. Our results indicate that NCCb is likely the key passive ion cotransporter protein for ion uptake by the lamprey intestine to facilitate water absorption in seawater. As such, the preparatory increases in intestinal nccb mRNA expression during metamorphosis are likely critical to the development of whole animal salinity tolerance.

scholarly journals Osmoregulatory role of the intestine in the sea lamprey (Petromyzon marinus)

2020 ◽  
Vol 318 (2) ◽  
pp. R410-R417 ◽  
Author(s):  
A. Barany ◽  
C. A. Shaughnessy ◽  
J. Fuentes ◽  
J. M. Mancera ◽  
S. D. McCormick
Keyword(s):  
Water Absorption ◽  
Salinity Tolerance ◽  
Ex Vivo ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Posterior Intestine ◽  
Direct Exposure ◽  
Plasma Chloride ◽  
Anterior Intestine

Lampreys are the most basal vertebrates with an osmoregulatory strategy. Previous research has established that the salinity tolerance of sea lamprey increases dramatically during metamorphosis, but underlying changes in the gut have not been examined. In the present work, we examined changes in intestinal function during metamorphosis and seawater exposure of sea lamprey ( Petromyzon marinus). Fully metamorphosed juvenile sea lamprey had 100% survival after direct exposure to 35 parts per thousand seawater (SW) and only slight elevations in plasma chloride (Cl−) levels. Drinking rates of sea lamprey juveniles in seawater were 26-fold higher than juveniles in freshwater (FW). Na+-K+-ATPase (NKA) activity in the anterior and posterior intestine increased 12- and 3-fold, respectively, during metamorphosis, whereas esophageal NKA activity was lower than in the intestine and did not change with development. Acclimation to SW significantly enhanced NKA activity in the posterior intestine but did not significantly change NKA activity in the anterior intestine, which remained higher than that in the posterior intestine. Intestinal Cl− and water uptake, which were observed in ex vivo preparations of anterior and posterior intestine under both symmetric and asymmetric conditions, were higher in juveniles than in larvae and were similar in magnitude of those of teleost fish. Inhibition of NKA by ouabain in ex vivo preparations inhibited intestinal water absorption by 64%. Our results indicate drinking and intestinal ion and water absorption are important to osmoregulation in SW and that preparatory increases in intestinal NKA activity are important to the development of salinity tolerance that occurs during sea lamprey metamorphosis.

scholarly journals The role of the rectum in osmoregulation and the potential effect of renoguanylin on SLC26a6 transport activity in the Gulf toadfish (Opsanus beta)

2016 ◽  
Vol 311 (1) ◽  
pp. R179-R191 ◽  
Author(s):  
Ilan M. Ruhr ◽  
Yoshio Takei ◽  
Martin Grosell
Keyword(s):  
Water Absorption ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Potential Effect ◽  
Posterior Intestine ◽  
Distal Intestine ◽  
Opsanus Beta ◽  
Ion Absorption ◽  
Gulf Toadfish

Teleosts living in seawater continually absorb water across the intestine to compensate for branchial water loss to the environment. The present study reveals that the Gulf toadfish ( Opsanus beta) rectum plays a comparable role to the posterior intestine in ion and water absorption. However, the posterior intestine appears to rely more on SLC26a6 (a HCO3−/Cl− antiporter) and the rectum appears to rely on NKCC2 (SLC12a1) for the purposes of solute-coupled water absorption. The present study also demonstrates that the rectum responds to renoguanylin (RGN), a member of the guanylin family of peptides that alters the normal osmoregulatory processes of the distal intestine, by inhibited water absorption. RGN decreases rectal water absorption more greatly than in the posterior intestine and leads to net Na+ and Cl− secretion, and a reversal of the absorptive short-circuit current ( ISC). It is hypothesized that maintaining a larger fluid volume within the distal segments of intestinal tract facilitates the removal of CaCO3 precipitates and other solids from the intestine. Indeed, the expression of the components of the Cl−-secretory response, apical CFTR, and basolateral NKCC1 (SLC12a2), are upregulated in the rectum of the Gulf toadfish after 96 h in 60 ppt, an exposure that increases CaCO3 precipitate formation relative to 35 ppt. Moreover, the downstream intracellular effects of RGN appear to directly inhibit ion absorption by NKCC2 and anion exchange by SLC26a6. Overall, the present findings elucidate key electrophysiological differences between the posterior intestine and rectum of Gulf toadfish and the potent regulatory role renoguanylin plays in osmoregulation.

Somatostatin-related peptides isolated from the eel gut: effects on ion and water absorption across the intestine of the seawater eel.

1994 ◽  
Vol 188 (1) ◽  
pp. 205-216 ◽  
Author(s):  
T Uesaka ◽  
K Yano ◽  
M Yamasaki ◽  
K Nagashima ◽  
M Ando
Keyword(s):  
Amino Acid ◽  
Water Absorption ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Neuronal Firing ◽  
European Eel ◽  
Amino Acid Residues ◽  
Stimulatory Action ◽  
Adrenergic Antagonist ◽  
Large Peptide

Four somatostatin-related peptides were isolated from eel guts. Two of them were the same as eel SS-25II (eSS-25II) and eel SS-25I (eSS-25I) isolated from European eel pancreas. The remaining two peptides were C-terminal tetradecapeptides (eSS-14II and eSS-14I) of eSS-25II and eSS-25I, respectively. These four peptides all enhanced the serosa-negative transepithelial potential difference and short-circuit current across the seawater eel intestine after pretreatment with isobutylmethylxanthine, serotonin (5-HT) and methacholine, an agonist of acetylcholine (ACh). Among these peptides, eSS-25II was the most potent enhancer, followed by eSS-25I and eSS-14II. Since the large peptide (eSS-25II) acts at a lower concentration than the small somatostatin (eSS-14II), the 11 N-terminal amino acid residues seem to potentiate somatostatin action in the eel intestine. In contrast, eSS-14II was more potent than mammalian SS-14, indicating that the three amino acid residues (Tyr18, Gly21, Pro22) in the C-terminal portion also contribute to the potency of somatostatin. Endogenous somatostatin (eSS-25II) activated net Na+, Cl- and water fluxes across the seawater eel intestine. This stimulatory action was not inhibited by tetrodotoxin or yohimbine, an adrenergic antagonist, indicating that eSS-25II does not act through neuronal firing or through catecholamine release. Thus, eel somatostatins may act directly on the enterocytes, but on a distinct receptor from that for adrenaline, to antagonize the inhibition of NaCl and water absorption by 5-HT and ACh in the seawater eel intestine.

scholarly journals Heme Impairs Alveolar Epithelial Sodium Channels Post Toxic Gas Inhalation

2020 ◽  
Author(s):  
Saurabh Aggarwal ◽  
Ahmed Lazrak ◽  
Israr Ahmad ◽  
Zhihong Yu ◽  
Ayesha Bryant ◽  
...  
Keyword(s):  
Pulmonary Edema ◽  
Ex Vivo ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Inhalation Injury ◽  
Alveolar Cells ◽  
Alveolar Epithelial ◽  
Single Intramuscular Injection ◽  
Free Heme ◽  
Gas Inhalation

ABSTRACTWe previously reported that cell-free heme (CFH) is increased in the plasma of patients with acute and chronic lung injury and causes pulmonary edema in animal model of acute respiratory distress syndrome (ARDS) post inhalation of halogen gas. However, the mechanisms by which CFH causes pulmonary edema are unclear. Herein we report for the first time the presence of CFH and chlorinated lipids (formed by the interaction of halogen gas, Cl2, with plasmalogens) in the plasma of patients and mice exposed to Cl2 gas. Ex vivo incubation of red blood cells (RBC) with halogenated lipids caused oxidative damage to RBC cytoskeletal protein spectrin, resulting in hemolysis and release of CFH. A single intramuscular injection of the heme-scavenging protein hemopexin (4 µg/kg body weight) in mice, one hour post halogen exposure, reversed RBC fragility and decreased CFH levels to those of air controls. Patch clamp and short circuit current measurements revealed that CFH inhibited the activity of amiloride-sensitive (ENaC) and cation sodium (Na+) channels in mouse alveolar cells and trans-epithelial Na+ transport across human airway cells with EC50 of 125 nM and 500 nM, respectively. Molecular modeling identified 22 putative heme-docking sites on ENaC (energy of binding range: 86-1563 kJ/mol) with at least 2 sites within its narrow transmembrane pore, potentially capable of blocking Na+ transport across the channel. In conclusion, results suggested that CFH mediated inhibition of ENaC activity may be responsible for pulmonary edema post inhalation injury.

O2-induced ENaC expression is associated with NF-κB activation and blocked by superoxide scavenger

1998 ◽  
Vol 275 (4) ◽  
pp. L764-L770 ◽  
Author(s):  
Bijan Rafii ◽  
A. Keith Tanswell ◽  
Gail Otulakowski ◽  
Olli Pitkänen ◽  
Rose Belcastro-Taylor ◽  
...  
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Nuclear Factor Κb ◽  
Lung Epithelial Cells ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Lung Epithelial ◽  
Distal Lung ◽  
Superoxide Scavenger ◽  
Transcription Factor Nuclear Factor

Cultured rat fetal distal lung epithelial cells (FDLEs), when switched from fetal (3%) to postnatal (21%) O2 concentrations, have increased epithelial Na+ channel (ENaC) mRNA levels and amiloride-sensitive Na+transport [O. Pitkänen, A. K. Tanswell, G. Downey, and H. O’Brodovich. Am. J. Physiol. 270 ( Lung Cell. Mol. Physiol. 14): L1060–L1066, 1996]. The mechanisms by which O2 mediates these effects are unknown. After isolation, FDLEs were kept at 3% O2 overnight, then switched to 21% O2 (3–21% O2 group) or maintained at 3% O2 (3–3% O2 group) for 48 h. The amiloride-sensitive short-circuit current ( I sc) in the 3–21% O2 group was double that in the 3–3% O2 group. Amiloride-sensitive I sc could not be induced by medium conditioned by 21% O2-exposed FDLEs but was reversed by returning the cells to 3% O2. Neither the cyclooxygenase inhibitor ibuprofen, liposome-encapsulated catalase, nor hydroperoxide scavengers (U-74389G or Trolox) blocked the O2-induced amiloride-sensitive I sc. In contrast, the cell-permeable superoxide scavenger tetramethylpiperidine- N-oxyl (TEMPO) eliminated the O2-induced increases in amiloride-sensitive I sc and ENaC mRNA levels. The switch from 3 to 21% O2 induced the transcription factor nuclear factor-κB, which could also be blocked by TEMPO. We conclude that 1) the O2-induced increase in amiloride-sensitive I sc is reversible and 2) the O2-induced increase in amiloride-sensitive I sc and ENaC mRNA levels is associated with activation of nuclear factor-κB and may be mediated, at least in part, by superoxide.

scholarly journals 11-Deoxycortisol is a stress responsive and gluconeogenic hormone in a jawless vertebrate, the sea lamprey (Petromyzon marinus)

2021 ◽  
Author(s):  
Ciaran A. Shaughnessy ◽  
Stephen D. McCormick
Keyword(s):  
Plasma Glucose ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Ex Vivo ◽  
Petromyzon Marinus ◽  
Regulatory Protein ◽  
Intraperitoneal Administration ◽  
Sea Lamprey ◽  
Mrna Levels ◽  
Binding Studies ◽  
Handling Stress

Although corticosteroid-mediated hepatic gluconeogenic activity in response to stress has been extensively studied in fishes and other vertebrates, there is little information on the stress response in basal vertebrates. In sea lamprey (Petromyzon marinus), a representative member of the most basal extant vertebrate group Agnatha, 11-deoxycortisol and deoxycorticosterone are the major circulating corticosteroids. The present study examined changes in circulating glucose and 11-deoxycortisol concentrations in response to a physical stressor. Furthermore, the gluconeogenic actions of 11-deoxycortisol and deoxycorticosterone were examined. Within 6 h after exposure of larval and juvenile sea lamprey to an acute handling stress, plasma 11-deoxycortisol levels increased 15- and 6-fold, respectively, and plasma glucose increased 3- and 4-fold, respectively. Radiometric receptor binding studies revealed that a corticosteroid receptor (CR) is present in the liver at lower abundance than other tissues (gill and anterior intestine) and that the binding affinity of the liver CR was similar for 11-deoxycortisol and deoxycorticosterone. Transcriptional tissue profiles indicate a wide distribution of cr transcription, kidney-specific transcription of steroidogenic acute regulatory protein (star), and liver-specific transcription of phosphoenolpyruvate carboxykinase (pepck). Ex vivo incubation of liver tissue with 11-deoxycortisol resulted in dose-dependent increases in pepck mRNA levels. Finally, intraperitoneal administration of 11-deoxycortisol and deoxycorticosterone demonstrated that only 11-deoxycortisol resulted in an increase in plasma glucose. Together, these results provide the first direct evidence for the gluconeogenic activity of 11-deoxycortisol in an Agnathan, indicating that corticosteroid regulation of plasma glucose is a basal trait among vertebrates.

Functional and molecular biological evidence of SGLT-1 in the ruminal epithelium of sheep

2000 ◽  
Vol 279 (1) ◽  
pp. G20-G27 ◽  
Author(s):  
Jörg R. Aschenbach ◽  
Heike Wehning ◽  
Martina Kurze ◽  
Elisabeth Schaberg ◽  
Hermann Nieper ◽  
...  
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Short Chain Fatty Acids ◽  
Glucose Absorption ◽  
Minor Importance ◽  
Mrna Levels ◽  
Ussing Chambers ◽  
Ruminal Epithelium ◽  
Cloned Cdna ◽  
Mucosal Side

Because of the effective catabolism ofd-glucose to short-chain fatty acids by intraruminal microorganisms, the absorption of d-glucose from the rumen was thought to be of minor importance. However, clinical studies suggested that significant quantities of d-glucose are transported from the ruminal contents to the blood. We therefore tested the ruminal epithelium of sheep for the presence of Na+-glucose cotransporter 1 (SGLT-1) on both the functional and mRNA levels. In the absence of an electrochemical gradient, 3- O-methylglucose (3-OMG) was net absorbed across isolated ruminal epithelia mounted in Ussing chambers. The net transport of 3-OMG followed Michaelis-Menten kinetics and was sensitive to phlorizin or decreasing Na+concentrations. The mucosal addition of 10 mM d-glucose induced an immediate, phlorizin-sensitive increase in short-circuit current ( Isc). Isccould also be increased by serosal addition of d-glucose or d-mannose, but electrogenic uptake of d-glucose or 3-OMG added on the mucosal side was still detectable after serosal stimulation of Isc. RT-PCR using primers specific for the ovine intestinal SGLT-1 with subsequent TA cloning and sequencing revealed 100% identity between the cloned cDNA and mRNA fragment 187–621 of ovine intestinal SGLT-1. In conclusion, the ruminal epithelium has a high-affinity SGLT-1, which indicates that it maintains the capacity for d-glucose absorption.

Oxygen induction of epithelial Na+ transport requires heme proteins

2000 ◽  
Vol 278 (2) ◽  
pp. L399-L406 ◽  
Author(s):  
Bijan Rafii ◽  
Chris Coutinho ◽  
Gail Otulakowski ◽  
Hugh O'Brodovich
Keyword(s):  
Mrna Expression ◽  
Heme Proteins ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Iron Chelator ◽  
Mrna Levels ◽  
Hypoxic Conditions ◽  
Lung Epithelial ◽  
Distal Lung ◽  
Iron Chelator Deferoxamine

Fetal distal lung epithelial (FDLE) cells exposed to a postnatal O2 concentration of 21% have higher epithelial Na+ channel (ENaC) mRNA levels and Na+ transport relative to FDLE cells grown in a fetal O2 concentration of 3%. To investigate the mechanism of this process, FDLE monolayers were initially cultured in 3% O2, and then some were switched to a 21% O2environment. Incubation of FDLE cells with the iron chelator deferoxamine, CoCl2, NiCl2, or an inhibitor of heme synthesis prevented or diminished the O2induction of amiloride-sensitive short-circuit current in FDLE cells. Similarly, defer- oxamine and cobalt prevented O2-induced ENaC mRNA expression. Exposure of FDLE cells grown under hypoxic conditions to carbon monoxide increased both ENaC mRNA expression and amiloride-sensitive short-circuit current. We therefore concluded that induction of ENaC mRNA expression and amiloride-sensitive Na+ transport in FDLE cells by a physiological increase in O2 concentration seen at birth requires iron and heme proteins.

Effect of sorbin on electrolyte transport in rat and human intestine

1999 ◽  
Vol 276 (1) ◽  
pp. G107-G114 ◽  
Author(s):  
Bruno Eto ◽  
Michel Boisset ◽  
Bertrand Griesmar ◽  
Jehan-François Desjeux
Keyword(s):  
Water Absorption ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrolyte Transport ◽  
Secretory Diarrhea ◽  
Maximal Effect ◽  
Human Intestine ◽  
Ussing Chambers ◽  
Antisecretory Effect ◽  
Dose Dependent

Stimulating water absorption in the colon represents an important target to reduce stool output in secretory diarrhea. Recently, a 153-amino-acid peptide was isolated from porcine upper small intestine and purified, taking into account the increase of water absorption in guinea pig gallbladder. Accordingly, this peptide was named sorbin. The aim of the present study was to determine if the COOH-terminal heptapeptide of sorbin (C7-sorbin) participates in the regulation of electrolyte transport in the colon. Different regions (from duodenum to colon) of stripped intestinal mucosa from rats or humans were mounted in Ussing chambers to measure the changes in short-circuit current (Δ Isc) and net22Na and36Cl fluxes ([Formula: see text] and[Formula: see text]) after serosal exposure of 10−7to 10−3M C7-sorbin. In fasted rat intestine, C7-sorbin (10−4M) induced an immediate reduction in Iscin the distal ileum and proximal and distal colon but not in the duodenum and jejunum. In the colon, Iscreduction and[Formula: see text] and[Formula: see text] stimulation were dose dependent (EC50= 2 × 10−5M). At 10−3M, maximal effect was observed (Δ Isc= −1.14 ± 0.05, Δ[Formula: see text] = +4.97 ± 1.38, and Δ[Formula: see text] = +9.25 ± 1.44 μeq ⋅ h−1⋅ cm−2). C7-sorbin (10−3M) inhibited the increase in Iscinduced by a series of 10 secretory agents such as secretin, vasoactive intestinal peptide, PGE2, and serotonin. In HT-29-Cl19A cells, C7-sorbin induced an increase in Isc, with a maximal effect at 10−3M (Δ Isc= 0.29 ± 0.10 μeq ⋅ h−1⋅ cm−2). In human intestine, a dose-dependent decrease in Iscwas observed in right and sigmoid colons in basal and stimulated conditions (EC50≅ 10−5M; at 10−4M, Δ Isc= −2.66 ± 0.17 μeq ⋅ h−1⋅ cm−2) but not in the jejunum. The results indicate that C7-sorbin stimulated NaCl neutral absorption and inhibited electrogenic Cl−in rat and human intestinal epithelia. In addition, the antisecretory effect was essentially observed in the distal part of both rat and human intestine and the magnitude of the proabsorptive effect was directly related to the magnitude of the previously induced secretion.

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