scholarly journals Sodium Efflux and Potential Differences across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 64 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Lewis Greenwald ◽  
Leonard B. Kirschner ◽  
Martin Sanders
Keyword(s):  
Rainbow Trout ◽  
Sea Water ◽  
Irrigation System ◽  
Body Fluids ◽  
Salmo Gairdneri ◽  
Adequate Model ◽  
Sodium Efflux ◽  
Order Of Magnitude ◽  
Sodium Extrusion ◽  
Trout Gill

Sodium extrusion (JoutNa) was measured across the gills of rainbow trout, Salmo gairdneri, adapted to sea water (SW) using a gill-irrigation system of small volume. The potential difference (TEP) was also measured under similar conditions. JoutNa was usually between 100–250 µeq (100 g)–1 h–1, about an order of magnitude faster than in fresh water (FW)-adapted trout, but slower than has been reported for any other marine teleost. The TEP was between 10–11 mV, body fluids positive to SW. When the external medium was changed from SW to FW JoutNa was reduced to about 25 % of the initial value, and the TEP was reduced by 40–50 mV (i.e. body fluids negative by 30–40 mV). Addition of either Na+ or K+ in SW concentrations reversed the changes; JoutNa increased and the gill repolarized. The electrical behavior and sodium efflux in irrigated trout gill is qualitatively the same as has been reported for unanaesthetized, free-swimming fish of other species. Thus, the irrigated gill provides an adequate model for studying the mechanism of sodium extrusion in marine teleosts.

scholarly journals On the Mechanism of Sodium Extrusion across the Irrigated Gill of Sea Water-Adapted Rainbow Trout (Salmo gairdneri)

1974 ◽  
Vol 64 (2) ◽  
pp. 148-165 ◽  
Author(s):  
Leonard B. Kirschner ◽  
Lewis Greenwald ◽  
Martin Sanders
Keyword(s):  
Rainbow Trout ◽  
Active Component ◽  
Sea Water ◽  
Salmo Gairdneri ◽  
Sodium Efflux ◽  
Exchange Diffusion ◽  
The Difference ◽  
Sodium Extrusion ◽  
Trout Gill ◽  
Electrical Data

Sodium efflux (JoutNa) across the irrigated trout gill was rapid in sea water (SW), but only about 25 % as large in fresh water (FW). The difference correlated with a change in the potential difference across the gill (TEP). The latter was about +10 mV (blood positive) in SW, but –40 mV in FW. Both flux and electrical data indicated that gills in this fish are permeable to a variety of cations including Na+, K+, Mg2+, choline, and Tris. They are less permeable to anions; PNa:PK:PCl was estimated to be 1:10:0.3, and PCl > Pgluconate. The TEP was shown to be a diffusion potential determined by these permeabilities and the extant ionic gradients in SW, FW as well as in other media. JoutNa appeared to be diffusive in all of the experiments undertaken. Exchange diffusion need not be posited, and the question of whether there is an active component remains open.

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.

The Effect of External Potassium Ions on the Electrical Potential Measured Across the Gills of the Teleost, Dormitator Maculatus

1974 ◽  
Vol 61 (2) ◽  
pp. 277-283
Author(s):  
DAVID H. EVANS ◽  
JEFFREY C. CARRIER ◽  
MARGARET B. BOGAN
Keyword(s):  
Sea Water ◽  
Electrical Potential ◽  
Potassium Ions ◽  
Sodium Efflux ◽  
Electrical Potentials ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium Extrusion ◽  
Sufficient Magnitude ◽  
Stimulation Of

1. A technique has been developed for the measurement of electrical potentials (TGP's) across the gills of free-swimming, Dormitator maculatus. 2. Transfer of fish to various KCl solutions is correlated with changes in the TGP, which are not of sufficient magnitude to account for the known potassium stimulation of sodium efflux from this species. 3. Transfer to potassium-free sea water results in little or no change in TGP while previous results have shown that such a transfer is correlated with a 22% reduction of sodium efflux. 4. Transfer to fresh water results in a reduction of TGP from +17 mV (inside positive) to -36 mV which is sufficient to account for the instantaneous reduction in sodium efflux previously shown for this species. 5. It is concluded that while changes in TGP can account for the ‘Na-free effect’ in D. maculatus they cannot account for the potassium effects on sodium extrusion. This supports the previous conclusion that sodium efflux and potassium influx are chemically linked in this species.

Onset and rate of drinking in rainbow trout (Salmo gairdneri) following transfer to dilute seawater

1979 ◽  
Vol 57 (10) ◽  
pp. 1863-1865 ◽  
Author(s):  
Roger M. Evans
Keyword(s):  
Rainbow Trout ◽  
Water Balance ◽  
Water Loss ◽  
Sea Water ◽  
Direct Method ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Salmo Gairdneri ◽  
Normal Water ◽  
A Direct Method

Seawater-adapted teleosts drink to offset water loss by osmosis. A direct method of monitoring drinking by implanting a fistula to drain the stomach indicated that rainbow trout began drinking from about 9 to 12 (range 1 to 22) h after being placed in 15‰ sea water. Unlike the Japanese eel (Anguilla japonica). in which the onset of drinking has been shown to be immediate and reflex-like, the onset of drinking in trout appears to occur only after appreciable water has been lost to the medium. The trout resembles the eel in that the capacity to shallow water in the absence of postingestional negative feedback exceeds the rate of drinking required to maintain normal water balance.

The Influence of pH, Water Hardness, and Alkalinity on the Acute Lethality of Zinc to Rainbow Trout (Salmo gairdneri)

1985 ◽  
Vol 42 (4) ◽  
pp. 731-736 ◽  
Author(s):  
R. W. Bradley ◽  
J. B. Sprague
Keyword(s):  
Rainbow Trout ◽  
Water Hardness ◽  
Salmo Gairdneri ◽  
Total Hardness ◽  
Zinc Toxicity ◽  
Carbonate Alkalinity ◽  
Effects Of Ph ◽  
Order Of Magnitude ◽  
Low Toxicity ◽  
Influence Of Ph

The acute lethality of dissolved zinc to rainbow trout (Salmo gairdneri) was significantly increased at higher pH and lower hardness levels. Changes in pH from 5.5 to 7.0 increased zinc toxicity by factors of 2 to 5, depending on total hardness levels. A decrease in hardness from 386 to 31 mg CaCO3/L increased zinc toxicity by more than an order of magnitude at both pH levels. These effects of pH and hardness were not caused by changes in the chemical speciation of zinc. An increase in carbonate alkalinity from 8.4 to 24 mg CaCO3/L at pH 7.0 did not significantly alter zinc toxicity at either hardness level. Thus, carbonate alkalinity is not an important factor at or below pH 7.0. At low hardness, dissolved zinc was more than 10 times as toxic at pH 9.0 as at pH 5.5. Two competing mechanisms appear to operate: as the pH rises, dissolved zinc becomes increasingly toxic, but at higher pH levels it is increasingly replaced by zinc precipitate, which is of very low toxicity to fish.

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