TY - JOUR
T1 - In vitro characterization of cadmium transport along the gastro-intestinal tract of freshwater rainbow trout (Oncorhynchus mykiss)
AU - Klinck, Joel S.
AU - Wood, Chris M.
N1 - Funding Information:
This research was supported in part by a Natural Sciences and Engineering Research Council of Canada Strategic Grant , with contributions from Rio Tinto Alcan and Environment Canada, and in part by an NSERC CRD Grant with contributions from the following industrial partners—the International Copper Association, the Copper Development Association, the Nickel Producers Environmental Research Association, the International Lead Zinc Research Organization, the International Zinc Association, Xstrata Zinc, Teck Resources, and Vale Inco. We thank Peter Chapman of Golder Associates, Sunita Nadella, Sara Klinck, and the two anonymous reviewers, for their constructive comments. JK is supported by an NSERC postgraduate scholarship, and CMW is supported by the Canada Research Chair Program. All experiments were in compliance with regulations set by the Canadian Council on Animal Care.
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/3
Y1 - 2011/3
N2 - An in vitro gut sac technique was used to examine the mechanism(s) of cadmium (Cd) uptake along the gastro-intestinal tract (GIT) of rainbow trout (Oncorhynchus mykiss). The spatial distribution of Cd between three compartments (mucus-binding, mucosal epithelium, and transport into blood space) was determined using a modified Cortland saline containing 50μM Cd (as CdCl2) labeled with 109Cd radiotracer. Taking into account total surface areas, the order of relative importance for total Cd uptake rate was: posterior intestine>anterior intestine>stomach>mid intestine. Cd transport was not inhibited by experimentally reducing fluid transport rates by manipulation of osmotic gradients using mannitol, but was sensitive to internal luminal pressure changes, suggesting a mechanosensitive pathway. Q10 values (1, 11, and 19°C) indicated a facilitated transport of Cd in the anterior- and mid-intestine. The effects of 10mM Ca on the kinetics of Cd uptake suggest the presence of a common uptake pathway for Cd and Ca in the stomach, anterior-, and mid-intestine. Further evidence of a shared route of entry was found using three Ca channel blockers, lanthanum, verapamil, and nifedipine: both voltage-insensitive and voltage-sensitive Ca channels appear to be present in either some, or all portions of the GIT. Elevated Fe (500μM), Mg (50mM), and Zn (500μM) showed varying degrees of inhibition of Cd transport depending on the compartment and segment of the GIT. Overall it appears that there are multiple sites, and mechanisms, of Cd uptake along the GIT of rainbow trout.
AB - An in vitro gut sac technique was used to examine the mechanism(s) of cadmium (Cd) uptake along the gastro-intestinal tract (GIT) of rainbow trout (Oncorhynchus mykiss). The spatial distribution of Cd between three compartments (mucus-binding, mucosal epithelium, and transport into blood space) was determined using a modified Cortland saline containing 50μM Cd (as CdCl2) labeled with 109Cd radiotracer. Taking into account total surface areas, the order of relative importance for total Cd uptake rate was: posterior intestine>anterior intestine>stomach>mid intestine. Cd transport was not inhibited by experimentally reducing fluid transport rates by manipulation of osmotic gradients using mannitol, but was sensitive to internal luminal pressure changes, suggesting a mechanosensitive pathway. Q10 values (1, 11, and 19°C) indicated a facilitated transport of Cd in the anterior- and mid-intestine. The effects of 10mM Ca on the kinetics of Cd uptake suggest the presence of a common uptake pathway for Cd and Ca in the stomach, anterior-, and mid-intestine. Further evidence of a shared route of entry was found using three Ca channel blockers, lanthanum, verapamil, and nifedipine: both voltage-insensitive and voltage-sensitive Ca channels appear to be present in either some, or all portions of the GIT. Elevated Fe (500μM), Mg (50mM), and Zn (500μM) showed varying degrees of inhibition of Cd transport depending on the compartment and segment of the GIT. Overall it appears that there are multiple sites, and mechanisms, of Cd uptake along the GIT of rainbow trout.
KW - Ca channel blockers
KW - Cadmium
KW - Calcium
KW - Gastro-intestinal tract
KW - Oncorhynchus mykiss
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U2 - 10.1016/j.aquatox.2010.12.009
DO - 10.1016/j.aquatox.2010.12.009
M3 - Article
C2 - 21371613
AN - SCOPUS:78951486584
VL - 102
SP - 58
EP - 72
JO - Aquatic Toxicology
JF - Aquatic Toxicology
SN - 0166-445X
IS - 1-2
ER -