In vitro characterization of cadmium transport along the gastro-intestinal tract of freshwater rainbow trout (Oncorhynchus mykiss)

Joel S. Klinck, Chris M. Wood

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)58-72
Number of pages15
JournalAquatic Toxicology
Volume102
Issue number1-2
DOIs
StatePublished - Mar 1 2011

    Fingerprint

Keywords

  • Ca channel blockers
  • Cadmium
  • Calcium
  • Gastro-intestinal tract
  • Oncorhynchus mykiss

ASJC Scopus subject areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis

Cite this