scholarly journals On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri)

1970 ◽  
Vol 56 (3) ◽  
pp. 342-359 ◽  
Author(s):  
Theodore H. Kerstetter ◽  
Leonard B. Kirschner ◽  
Donald D. Rafuse
Keyword(s):  
Rainbow Trout ◽  
Small Volume ◽  
Salmo Gairdneri ◽  
Sodium Influx ◽  
Rate Limiting Step ◽  
Counter Ions ◽  
Flux Measurements ◽  
Type Relation ◽  
Rate Limiting ◽  
Na Uptake

Sodium uptake by rainbow trout gills has been investigated with a small-volume system enabling rapid, successive flux measurements in different solutions. Sodium influx obeys a Michaelis-Menten type relation, with a Km of 0.46 mM, and uptake proceeds unimpaired in the absence of penetrating counter-ions. This suggests a coupled cation exchange. Ammonia output is about the same as the Na+ influx when external [Na+] is 1 mM, but at higher or lower Na+ influxes, the correlation does not hold. A progressive downward shift in the pH of the irrigating medium as Na+ influx increases indicates that the exchanging cation is hydrogen. In support of this, acetazolamide, which inhibits Na+ uptake, also prevents the downward pH shift. The potential across the gill is about 10 mv, body fluids positive, in NaCl solutions up to 10 mM, and is little affected by changes in Na+ concentration below that. Finally, evidence for locating the rate-limiting step at the outer membrane of the epithelium is presented.

Acid-Base Regulation Following Exhaustive Exercise: A Comparison Between Freshwaterand Sea Water-Adapted Rainbow Trout (Salmo Gairdneri)

1989 ◽  
Vol 141 (1) ◽  
pp. 407-418 ◽  
Author(s):  
Y. TANG ◽  
D. G. McDONALD ◽  
R. G. BOUTILIER
Keyword(s):  
Rainbow Trout ◽  
Sea Water ◽  
Environmental Water ◽  
Exhaustive Exercise ◽  
Salmo Gairdneri ◽  
Acid Base ◽  
Genetic Stock ◽  
Arterial Blood ◽  
Blood Ph ◽  
Counter Ions

Blood acid-base regulation following exhaustive exercise was investigated in freshwater- (FW) and seawater- (SW) adapted rainbow trout (Salmo gairdneri) of the same genetic stock. Following exhaustive exercise at 10°C, both FW and SW trout displayed a mixed respiratory and metabolic blood acidosis. However, in FW trout the acidosis was about double that of SW trout and arterial blood pH took twice as long to correct. These SW/FW differences were related to the relative amounts of net H+ equivalent excretion to the environmental water, SW trout excreting five times as much as FW trout. The greater H+ equivalent excretion in SW trout may be secondary to changes in the gills that accompany the adaptation from FW to SW. It may also be related to the higher concentrations of HCO3− as well as other exchangeable counter-ions (Na+ and Cl−) in the external medium in SW compared to FW.

Metabolism and Biliary Excretion of Sulfobromophthalein by Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (9) ◽  
pp. 1301-1308 ◽  
Author(s):  
Dana C. Schmidt ◽  
L. J. Weber
Keyword(s):  
Rainbow Trout ◽  
Half Life ◽  
Liver Blood Flow ◽  
Salmo Gairdneri ◽  
Blood Clearance ◽  
Spinal Transection ◽  
Blood Flows ◽  
Rate Limiting Step ◽  
Different Temperatures ◽  
Plasma Half Life

The plasma half-life of sulfobromophthalein (BSP) for rainbow trout (Salmo gairdneri) was 13 min for doses of 5 and 10 mg/kg and 29 min for a dose of 15 mg/kg. The biliary BSP transport maximum (Tm) averaged 9.6 μg/min per kg for five fish while the blood clearance averaged 1.7 ml/min per kg for two fish. Normal bile flows of 0.87 μliter/min per kg in trout were increased upon anesthetization but were unaffected in fish allowed to recover from spinal transection. Spinal transection did not affect the plasma half-life of BSP.The data presented support the conclusion that the transport of BSP from liver cells to bile is the rate-limiting step in the excretion of this dye. When the BSP Tm of trout was compared to literature values for mammals and dogfish (Squalus acanthias), large differences were found which were probably caused by effects of different temperatures and blood flows. When the Tm values of the various species were based on blood clearance of BSP (reflecting liver blood flow) the differences were greatly reduced, suggesting similar abilities of the liver of the various species to excrete this dye.

Time course analysis of the mechanism by which silver inhibits active Na+ and Cl− uptake in gills of rainbow trout

2004 ◽  
Vol 287 (1) ◽  
pp. R234-R242 ◽  
Author(s):  
Tammie P. Morgan ◽  
Martin Grosell ◽  
Kathleen M. Gilmour ◽  
Richard C. Playle ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Carbonic Anhydrase ◽  
Time Course ◽  
Carbonic Anhydrase Activity ◽  
Short Term ◽  
Progressive Decline ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Flow Through ◽  
Rate Limiting

A time course analysis using 110mAg, 24Na+, and 36Cl− examined gill silver accumulation and the mechanism by which waterborne silver (4.0 × 10−8 M; 4.3 μg/l) inhibits Na+ and Cl− uptake in gills of freshwater rainbow trout. Analyses of gill and body fluxes allowed calculation of apical uptake and basolateral export rates for silver, Na+, and Cl−. To avoid changes in silver bioavailability, flow-through conditions were used to limit the buildup of organic matter in the exposure water. For both Na+ and Cl− uptake, apical entry, rather than basolateral export, was the rate-limiting step; Na+ and Cl− uptake declined simultaneously and equally initially, with both uptakes reduced by ∼500 nmol·g−1·h−1 over the 1st h of silver exposure. There was a further progressive decline in Na+ uptake until 24 h. Carbonic anhydrase activity was inhibited by 1 h, whereas Na+-K+-ATPase activity was not significantly inhibited until 24 h of exposure. These results indicate that carbonic anhydrase inhibition can explain the early decline in Na+ and Cl− uptake, whereas the later decline is probably related to Na+-K+-ATPase blockade. Contrary to previous reports, gill silver accumulation increased steadily to a plateau. Despite the rapid inhibition of apical Na+ and Cl− uptake, apical silver uptake (and basolateral export) increased until 10 h, before decreasing thereafter. Thus silver did not inhibit its own apical uptake in the short term. These results suggest that reduced silver bioavailability is the mechanism behind the pattern of peak and decline in gill silver accumulation previously reported for static exposures to silver.

Ion Flux Rates, Acid–Base Status, and Blood Gases in Rainbow Trout, Salmo gairdneri, Exposed to Toxic Zinc in Natural Soft Water

1985 ◽  
Vol 42 (8) ◽  
pp. 1332-1341 ◽  
Author(s):  
Douglas J. Spry ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Metabolic Acidosis ◽  
Ammonia Excretion ◽  
Blood Gases ◽  
Soft Water ◽  
Salmo Gairdneri ◽  
Acid Base ◽  
Flux Measurements ◽  
Water Base ◽  
Toxic Concentrations

Exposure to 0.8 mg Zn2+/L in natural soft water for up to 72 h was toxic to rainbow trout, Salmo gairdneri, causing an acid–base disturbance and net branchial ion losses. Mean arterial pH fell from 7.78 to 7.58. Both [Formula: see text] and lactate rose, indicating a mixed respiratory and metabolic acidosis, despite maintenance of high [Formula: see text] Net branchial uptake of Na+ and Cl− became a net loss immediately following exposure to Zn2+, and this continued during 60 h of exposure. Net K+ loss was exacerbated, and net Ca2+ uptake was abolished. Unidirectional flux measurements with 22Na+ and 36Cl− indicated an increased efflux immediately following zinc exposure. Both influx and efflux of Na+ and Cl− were stimulated after 48–60 h in Zn2+. Both net branchial ammonia excretion and net branchial uptake of acidic equivalents from the water (=base loss) were greatly stimulated, the latter contributing to metabolic acidosis. Kidney function, as measured by urine flow rate and excretion of ammonia, acidic equivalents, Na+, Cl−, K+, and Zn2+, was relatively insensitive to the effects of zinc. The only renal component to be affected was Ca2+ excretion, which decreased during a single flux period, possibly in response to the reduced entry of Ca2+ at the gill. We conclude that toxic concentrations of zinc are capable of altering gill function so as to cause ionoregulatory and acid–base disturbances without disturbance of [Formula: see text].

On the interaction of NH+4 and Na+ fluxes in the isolated trout gill

1976 ◽  
Vol 64 (2) ◽  
pp. 517-527
Author(s):  
T. H. Kerstetter ◽  
M. Keeler
Keyword(s):  
Rainbow Trout ◽  
Transport Process ◽  
Gill Tissue ◽  
Transport Rate ◽  
Salmo Gairdneri ◽  
Appreciable Effect ◽  
Sodium Influx ◽  
Low Sodium ◽  
Trout Gill

1. Sodium influx was measured in isolated, previously perfused gill arches of rainbow trout, Salmo gairdneri, by measuring incorporation of 22Na into gill tissue following timed exposure to a 1 mM 22NaCl medium. Transport rates approximated those estimated for intact fish and were linear for at least one min. 2. NH4Cl-containing perfusates at pH 7 and 8 stimulated Na+ influx equally, indicating that only ionized ammonia is important in the transport process. A Na+/NH4+ exchange at basal and/or lateral membranes of the transporting cells is suggested. 3. Low-sodium Ringer perfusate augmented Na+ influx; in one group of gills the transport rate was more than double that of NaCl Ringer controls. The increase in transport induced by internal NH4+ was not additive with the low sodium augmentation. A reduction in intracellular (Na+) is postulated as the mechanism operating in both cases. 4. Ouabain had no appreciable effect on Na+ influx, either with or without NH4+ in the perfusate. Diamox partially blocked the augmented Na+ influx induced by NH4+. Amiloride completely inhibited Na+ influx, both with and without NH4+ in the perfusate.

Gill morphology and sodium influx in the rainbow trout (Salmo gairdneri) acclimated to artificial freshwater environments

1987 ◽  
Vol 241 (2) ◽  
pp. 159-169 ◽  
Author(s):  
Martine Avella ◽  
Armand Masoni ◽  
Michel Bornancin ◽  
Nicole Mayer-Gostan
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Sodium Influx ◽  
Gill Morphology ◽  
Freshwater Environments

Uptake of Organic Chemicals across Fish Gills: Alternatives to the Use of Fish Populations

1993 ◽  
Vol 21 (4) ◽  
pp. 453-456
Author(s):  
Dick T.H.M. Sijm
Keyword(s):  
Rainbow Trout ◽  
Fish Populations ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Uptake Rates ◽  
Fundamental Research ◽  
Animal Use ◽  
Rate Limiting

In this study, the isolated perfused gills of rainbow trout (Oncorhynchus mykiss) provided a tool for fundamental research on the rate-limiting step in the uptake of organic hydrophobic chemicals. Data obtained using the isolated gills were comparable to those determined in vivo. Whereas several tens of fish need to be used to obtain statistically sound information on uptake rates in vivo, the isolated perfused gills method requires only three or four fish. A significant reduction in animal use is thus obtained.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

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