The regulatory role of glucocorticoid and mineralocorticoid receptors in pulsatile urea excretion of the gulf toadfish, Opsanus beta

2009 ◽  
Vol 212 (12) ◽  
pp. 1849-1858 ◽  
Author(s):  
T. M. Rodela ◽  
M. D. McDonald ◽  
P. J. Walsh ◽  
K. M. Gilmour
Keyword(s):  
Regulatory Role ◽  
Mineralocorticoid Receptors ◽  
Opsanus Beta ◽  
Urea Excretion ◽  
Gulf Toadfish

scholarly journals A waterborne chemical cue from Gulf toadfish, Opsanus beta, prompts pulsatile urea excretion in conspecifics

2017 ◽  
Vol 171 ◽  
pp. 92-99 ◽  
Author(s):  
Jeremy Fulton ◽  
Christophe M.R. LeMoine ◽  
Carol Bucking ◽  
Kevin V. Brix ◽  
Patrick J. Walsh ◽  
...  
Keyword(s):  
Chemical Cue ◽  
Opsanus Beta ◽  
Urea Excretion ◽  
Gulf Toadfish

Guanylin peptides regulate electrolyte and fluid transport in the Gulf toadfish (Opsanus beta) posterior intestine

2014 ◽  
Vol 307 (9) ◽  
pp. R1167-R1179 ◽  
Author(s):  
Ilan M. Ruhr ◽  
Charlotte Bodinier ◽  
Edward M. Mager ◽  
Andrew J. Esbaugh ◽  
Cameron Williams ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Short Circuit ◽  
Secretory Response ◽  
Seawater Adaptation ◽  
Posterior Intestine ◽  
Ussing Chambers ◽  
Opsanus Beta ◽  
Anterior Intestine ◽  
Gulf Toadfish

The physiological effects of guanylin (GN) and uroguanylin (UGN) on fluid and electrolyte transport in the teleost fish intestine have yet to be thoroughly investigated. In the present study, the effects of GN, UGN, and renoguanylin (RGN; a GN and UGN homolog) on short-circuit current ( Isc) and the transport of Cl−, Na+, bicarbonate (HCO3−), and fluid in the Gulf toadfish ( Opsanus beta) intestine were determined using Ussing chambers, pH-stat titration, and intestinal sac experiments. GN, UGN, and RGN reversed the Isc of the posterior intestine (absorptive-to-secretory), but not of the anterior intestine. RGN decreased baseline HCO3− secretion, but increased Cl− and fluid secretion in the posterior intestine. The secretory response of the posterior intestine coincides with the presence of basolateral NKCC1 and apical cystic fibrosis transmembrane conductance regulator (CFTR), the latter of which is lacking in the anterior intestine and is not permeable to HCO3− in the posterior intestine. However, the response to RGN by the posterior intestine is counterintuitive given the known role of the marine teleost intestine as a salt- and water-absorbing organ. These data demonstrate that marine teleosts possess a tissue-specific secretory response, apparently associated with seawater adaptation, the exact role of which remains to be determined.

scholarly journals Revisiting the effects of crowding and feeding in the gulf toadfish, Opsanus beta: the role of Rhesus glycoproteins in nitrogen metabolism and excretion

2011 ◽  
Vol 215 (2) ◽  
pp. 301-313 ◽  
Author(s):  
T. M. Rodela ◽  
A. J. Esbaugh ◽  
D. Weihrauch ◽  
C. M. Veauvy ◽  
M. D. McDonald ◽  
...  
Keyword(s):  
Nitrogen Metabolism ◽  
Opsanus Beta ◽  
Gulf Toadfish

Molecular characterization of a urea transporter in the gill of the gulf toadfish (Opsanus beta)

2000 ◽  
Vol 203 (15) ◽  
pp. 2357-2364 ◽  
Author(s):  
P.J. Walsh ◽  
M.J. Heitz ◽  
C.E. Campbell ◽  
G.J. Cooper ◽  
M. Medina ◽  
...  
Keyword(s):  
Morphological Data ◽  
Northern Analysis ◽  
Xenopus Laevis Oocytes ◽  
Urea Transporter ◽  
Reading Frame ◽  
Opsanus Beta ◽  
Urea Excretion ◽  
Pulse Cycle ◽  
A Minor ◽  
Gulf Toadfish

Urea excretion by the gulf toadfish (Opsanus beta) has been shown in previous studies to be a highly pulsatile facilitated transport, with excretion probably occurring at the gill. The present study reports the isolation of an 1800 base pair (kb) cDNA from toadfish gill with one open reading frame putatively encoding a 475-residue protein, the toadfish urea transporter (tUT). tUT, the first teleostean urea transporter cloned, has high homology with UTs (facilitated urea transporters) cloned from mammals, an amphibian and a shark, and most closely resembles the UT-A subfamily. When expressed in Xenopus laevis oocytes, tUT increased urea permeability (as measured by [(14)C]urea uptake) five- to sevenfold, and this permeability increase was abolished by phloretin, a common inhibitor of other UTs. Northern analysis using the 1.8 kb clone was performed to determine the tissue distribution and dynamics of tUT mRNA expression. Of six tissues examined (gill, liver, red blood cells, kidney, skin and intestine), only gill showed expression of tUT mRNA, with a predominant band at 1.8 kb and a minor band at 3.5 kb. During several points in the urea pulse cycle of toadfish (0, 4, 6, 12 and 18 h post-pulse), measured by excretion of [(14)C]urea into the water, gill mRNA samples were obtained. Expression of tUT mRNA was found to be largely invariant relative to expression of beta-actin mRNA over the pulse cycle. These results further confirm the gill localization of urea transport in the toadfish and suggest that tUT regulation (and the regulation of pulsatile urea excretion) is probably not at the level of mRNA control. The results are discussed in the context of the mechanisms of vasopressin-regulated UT-A in mammalian kidney and morphological data for the toadfish gill.

Does Pulsatile Urea Excretion Serve as a Social Signal in the Gulf Toadfish Opsanus beta?

2005 ◽  
Vol 78 (5) ◽  
pp. 724-735 ◽  
Author(s):  
Katherine A. Sloman ◽  
M. Danielle McDonald ◽  
John F. Barimo ◽  
Olivier Lepage ◽  
Svante Winberg ◽  
...  
Keyword(s):  
Opsanus Beta ◽  
Urea Excretion ◽  
Social Signal ◽  
Gulf Toadfish

Extrinsic nerves are not involved in branchial 5-HT dynamics or pulsatile urea excretion in Gulf toadfish, Opsanus beta

2017 ◽  
Vol 214 ◽  
pp. 58-65 ◽  
Author(s):  
Maria C. Cartolano ◽  
Molly H.B. Amador ◽  
Velislava Tzaneva ◽  
William K. Milsom ◽  
M. Danielle McDonald
Keyword(s):  
Opsanus Beta ◽  
Urea Excretion ◽  
Extrinsic Nerves ◽  
Gulf Toadfish

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.

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