Evidence for an intrarenal renin-angiotensin system in the rainbow trout,<i>Oncorhynchus mykiss</i>

Brown, J. Anne; Paley, Richard; Amer, Shehla; Aves, Stephen J.

doi:10.1152/ajpregu.2000.278.6.r1685

Cited by 14 publications

(10 citation statements)

References 31 publications

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“…The perfused trunk preparation has been used in freshwater-acclimated rainbow trout Oncorhynchus mykiss for the investigation of renal actions of AVT (3,8) and ANG II (8,11). The present study is the first time that use of a perfused trunk preparation has been reported in an elasmobranch fish.…”

Section: Discussionmentioning

confidence: 83%

Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin

Wells

Anderson

Hazon

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin. Am J Physiol Regulatory Integrative Comp Physiol 282: R1636-R1642, 2002 10.1152/ajpregu.00810.2000.-Acclimation of the European lesser-spotted dogfish Scyliorhinus canicula to reduced environmental salinity [85-70% seawater (SW)] induced a significant diuresis in addition to a significant decrease in plasma osmolality in vivo. The threshold for this diuresis was determined to be 85% SW. Therefore, S. canicula acclimated to 85% SW was selected for further study as a diuretic model in the development of an in situ perfused kidney preparation. The renal role of arginine vasotocin (AVT) in the in situ perfused trunk preparation was investigated. In SW, perfusion of 10 Ϫ9 and 10 Ϫ10 M AVT resulted in a glomerular antidiuresis and decreases in tubular transport maxima for glucose and perfusate flow. In 85% SW, 10 Ϫ10 M AVT had no significant effect on these renal parameters with the exception of transport maxima for glucose and perfusate flow. Tubular parameters remained unchanged by either 10 Ϫ9 or 10 Ϫ10 M AVT. The results demonstrate that the perfused kidney preparation was a viable tool for the investigation of renal parameters in elasmobranch fish and that AVT induced a glomerular antidiuresis.antidiuresis; seawater; Scyliorhinus canicula; dogfish; neurohypophysial hormones MARINE ELASMOBRANCHS MAINTAIN their plasma isoosmotic or slightly hyperosmotic to that of the surrounding environment, primarily due to the retention of urea (22). Plasma sodium and chloride concentrations are generally higher than those found in marine teleosts, but the fish still face a continuous influx of NaCl across semipermeable membranes, particularly the gills (18,20). Due to the plasma iso/hyperosmolality, some influx of water will occur and urea will be lost to the environment across permeable surfaces, along a concentration gradient. Elasmobranchs are not capable of producing a hyperosmotic urine with respect to body fluids, and the kidneys are not the major site of NaCl excretion (17). It appears that renal retention of urea may be a more important function for the kidney in elasmobranch fish (7).Arginine vasotocin (AVT), a homologue of arginine vasopressin (AVP) in mammals, is the major neurohypophysial peptide in lower vertebrates. It has been characterized in all elasmobranchs examined to date (1, 2). In addition to AVT, the European lesserspotted dogfish Scyliorhinus canicula also has the oxytocinlike peptides, phasvatocin and asvatocin, which occur in roughly equal molar amounts in the pituitary (13). AVT is also present in the pituitary in a proportional amount that is lower by about a factor of 20 (13). This low pituitary level was thought to reflect a permanent secretion of AVT (2). Although accurate levels of AVT have been measured in teleosts, the presence of additional neurohypophysial peptides in elasmobranchs and the potential for these to cross-react with the antiserum have meant that it has not been possible at...

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Section: Discussionmentioning

confidence: 83%

Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin

Wells

Anderson

Hazon

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The TmG found in this study is similar to findings in another in vivo study (Gray and Brown, 1985;Table·2). However, it is approximately double compared with findings on in situ perfused trout kidney studies (Amer and Brown, 1995;Brown et al, 2000;Table·2). Part of these differences could be accounted for by variations in experimental temperatures, as TmG varies with temperature, with higher temperatures yielding higher TmGs (MacKay and Beatty, 1967).…”

Section: Discussionmentioning

confidence: 87%

Renal regulation of plasma glucose in the freshwater rainbow trout

Bucking

Wood

2005

Journal of Experimental Biology

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SUMMARY This study examined the effects of prolonged hyperglycemia on renal handling of glucose and explored the in vivo pharmacological effects of phlorizin on glucose transport in the rainbow trout. The transport of glucose was examined by experimentally elevating the rate of renal glucose reabsorption via infusion of the fish with exogenous glucose at a rate of 70 μmol kg–1 h–1 and by inactivating the glucose transporters via the simultaneous administration of phlorizin (1 μmol kg–1h–1). Glucose was reabsorbed against a concentration gradient, until plasma glucose levels reached ∼22 μmol l–1 and the transport maximum of glucose in the kidney(∼145 μmol kg–1 h–1) was exceeded. At this point, glucose was lost to the urine, resulting in glucosuria. Glucosuria affected water reabsorption, approximately doubling the water clearance ratio,and resulted in osmotic diuresis. This in turn reduced Na+reabsorption, increasing the amount lost to the urine from 0.5% to 2% of the filtered load. Glucose reabsorption was found to be correlated with Na+ reabsorption, though the latter was almost 10-fold higher than glucose transport rates. Phlorizin treatment reduced glucose reabsorption,although it did not block it entirely until 48–72 h of infusion. The glucosuria resulting from the blockade of the glucose transporters resulted in a similar osmotic diuresis and a greater Na+ loss to the urine (9%of filtered load). The results are discussed with respect to the net renal`wasting' of glucose and the detrimental osmoregulatory and ionoregulatory effects associated with glucosuria caused by carbohydrate-rich diets.

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“…Pressure effects would be very rapidly achieved and a restoration of blood pressure would be likely to inhibit further angiotensin formation. A further part of the recovery, at least in FWacclimated lampreys, could involve a reduction in urine flow rates initiated by angiotensin, as has been shown to occur in teleosts (Brown and Balment, 1997;Brown et al, 2000). Studies are required to describe fully the renal actions of the lamprey RAS, but Asn 1 ,Val 5 -Ang II at 10 -10 or 10 -9 ·mol·min -1 ·kg -1 ·body·mass has been shown to reduce urine flow rates of FW-acclimated Lampetra fluviatilis and Petromyzon marinus (J.…”

Section: Discussionmentioning

confidence: 93%

Activation of the newly discovered cyclostome renin–angiotensin system in the river lampreyLampetra fluviatilis

Brown

Cobb

Frankling

et al. 2005

Journal of Experimental Biology

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SUMMARY This study describes the first investigations of the physiological signals involved in activating the newly discovered cyclostome renin–angiotensin system (RAS) and its role in the river lamprey Lampetra fluviatilis. Experimental manipulation showed that volume depletion (removal of 40% blood volume) rapidly activated the RAS of lampreys acclimated to water at 576 mOsm kg–1 (21 p.p.t.), significantly increasing plasma angiotensin concentrations after 30 min and 60 min. In agreement with these results, a rapid change in environmental salinity (758 mOsm kg–1 to freshwater (FW) and FW to 605 mOsm kg–1), resulted in a rapid decrease and increase in plasma [angiotensin], respectively. Intraperitoneal(i.p.) injection of FW-acclimated river lampreys with 1% body mass by volume of nominally isosmotic saline (120 mmol l–1 NaCl; 233 mOsm kg–1) resulted in a significant decrease in the plasma angiotensin concentration within 15 min. In contrast, i.p. injection of hyperosmotic saline (4 mol l–1 NaCl) at 1% body mass by volume, which significantly increased plasma osmolality, had no significant effect on plasma [angiotensin], suggesting that volume/pressure receptors and osmoreceptors interact in regulating the lamprey RAS. These results indicate an important role for volume/pressor receptors, as in teleosts, but with an additional osmoreceptor mechanism, such that circulatory [angiotensin] is determined by interaction of volume/pressure and osmoreceptors and their relative sensitivities. The volume/pressure sensitivity is in keeping with the recent evidence of a vasoconstrictor action of homologous lamprey angiotensin and provides evidence that the fundamental role of the RAS in maintaining volume and pressure is an ancient function conserved over 500 million years of vertebrate evolution.

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Evidence for an intrarenal renin-angiotensin system in the rainbow trout,Oncorhynchus mykiss

Cited by 14 publications

References 31 publications

Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin

Development of an in situ perfused kidney preparation for elasmobranch fish: action of arginine vasotocin

Renal regulation of plasma glucose in the freshwater rainbow trout

Activation of the newly discovered cyclostome renin–angiotensin system in the river lampreyLampetra fluviatilis

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