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Titre du document / Document title

The mechanism of acute silver nitrate toxicity in freshwater rainbow trout (Oncorhynchus mykiss) is inhibition of gill Na+ and Cl transport

Auteur(s) / Author(s)

MORGAN I. J. (1) ; HENRY R. P. (2) ; WOOD C. M. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Biology Department, McMaster University, 1280 Main Street West, Hamilton, Ont., CANADA
(2) Department of Zoology and Wildlife Science, 101 Carey Hall, Auburn University, Auburn, AL, ETATS-UNIS

Résumé / Abstract

Copyright (c) 1997 Elsevier Science B.V. All rights reserved. Rainbow trout (Oncorhynchus mykiss) were exposed to 2 and 10μgl−1 silver (as AgNO3) for up to 75h in moderately hard freshwater. At 10μgl−1 total Ag, branchial Na+ and Cl influxes were inhibited by over 50% immediately and by almost 100% at 8h, and showed no signs of recovery over the duration of the experiment. Na+ and Cl effluxes were much less affected. These changes in unidirectional fluxes resulted in a large net loss of both Na+ and Cl across the gills and a significant decrease in plasma [Na+ and [Cl. The effects of exposure to 2μgl−1 Ag on Na+ and Cl transport were generally similar to those at 10μgl−1, but were of a lesser magnitude. Unidirectional Na+ fluxes recovered immediately after removal of silver, after 48h exposure to 2μgl−1. Michaelis−Menten kinetic analysis demonstrated that the maximal rate of Na+ influx (Jmax) was significantly reduced after 48h exposure to 2μgl−1 Ag, whereas the affinity of the transport sites for Na+ (1/Km) was unaffected, indicating that the inhibition of Na+ influx by silver was of a non-competitive nature. Fish exposed to 10μgl−1 Ag for 48h also had significantly lower activities of the branchial enzymes Na+/K+ ATPase (85% inhibition) and carbonic anhydrase (28% inhibition). The results of this study suggest that a disturbance of branchial ionoregulation, as a result of inhibition of branchial enzymes involved in ion transport, is the principal mechanism of the physiological toxicity of silver nitrate to freshwater fish.

Revue / Journal Title

Aquatic toxicology    ISSN  0166-445X   CODEN AQTODG 

Source / Source

1997, vol. 38, no1-3, pp. 145-163

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Amsterdam, PAYS-BAS  (1981) (Revue)

Mots-clés anglais / English Keywords

Silver nitrate

;

Pollutant

;

Toxicity

;

Inhibition

;

Ion transport

;

Sodium

;

Chlorine

;

Osmoregulation

;

Oncorhynchus mykiss

;

Salmonidae

;

Water pollution

;

Freshwater environment

;

Pisces

;

Vertebrata

;

Mots-clés français / French Keywords

Argent nitrate

;

Polluant

;

Toxicité

;

Inhibition

;

Transport ion

;

Sodium

;

Chlore

;

Osmorégulation

;

Oncorhynchus mykiss

;

Salmonidae

;

Pollution eau

;

Milieu eau douce

;

Pisces

;

Vertebrata

;

Mots-clés espagnols / Spanish Keywords

Plata nitrato

;

Contaminante

;

Toxicidad

;

Inhibición

;

Transporte iónica

;

Sodio

;

Cloro

;

Osmoregulación

;

Oncorhynchus mykiss

;

Salmonidae

;

Contaminación agua

;

Medio agua dulce

;

Pisces

;

Vertebrata

;

Localisation / Location

INIST-CNRS, Cote INIST : 18841, 35400006189352.0018

Nº notice refdoc (ud4) : 2765166



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