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Hormonal and environmental regulation of epithelial calcium channel in gill of rainbow trout (Oncorhynchus mykiss)

Hormonal and environmental regulation of epithelial calcium channel in gill of rainbow trout... We indirectly tested the idea that the epithelial Ca 2+ channel (ECaC) of the trout gill is regulated in an appropriate manner to adjust rates of Ca 2+ uptake. This was accomplished by assessing the levels of gill ECaC mRNA and protein in fish exposed to treatments known to increase or decrease Ca 2+ uptake capacity. Exposure of trout to soft water (Ca 2+ = 20–30 nmol/l) for 5 days (a treatment known to increase Ca 2+ uptake capacity) caused a significant increase in ECaC mRNA levels and an increase in ECaC protein expression. The inducement of hypercalcemia by infusing fish with CaCl 2 (a treatment known to reduce Ca 2+ uptake) was associated with a significant decrease in ECaC mRNA levels, yet protein levels were unaltered. ECaC mRNA and protein expression were increased in fish treated with the hypercalcemic hormone cortisol. Finally, exposure of trout to 48 h of hypercapnia (∼7.5 mmHg, a treatment known to increase Ca 2+ uptake capacity) elicited an ∼100-fold increase in the levels of ECaC mRNA and a significant increase in protein expression. Immunocytochemical analysis of the gills from hypercapnic fish suggested a marked increase in the apical expression of ECaC on pavement cells and a subpopulation of mitochondria-rich cells. The results of this study provide evidence that Ca 2+ uptake rates are, in part, regulated by the numbers of apical membrane Ca 2+ channels that, in turn, modulate the inward flux of Ca 2+ into gill epithelial cells. transient receptor potential vanilloid 6; hypercapnia; cortisol; hypercalcemia; soft water Address for reprint requests and other correspondence: S. Perry, Dept. of Biology, Center for Advanced Research in Environmental Genomics, Univ. of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5 Canada (e-mail sfperry@science.uottawa.ca ) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Regulatory, Integrative and Comparative Physiology The American Physiological Society

Hormonal and environmental regulation of epithelial calcium channel in gill of rainbow trout (Oncorhynchus mykiss)

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References (49)

Publisher
The American Physiological Society
Copyright
Copyright © 2011 the American Physiological Society
ISSN
0363-6119
eISSN
1522-1490
DOI
10.1152/ajpregu.00026.2006
pmid
16763083
Publisher site
See Article on Publisher Site

Abstract

We indirectly tested the idea that the epithelial Ca 2+ channel (ECaC) of the trout gill is regulated in an appropriate manner to adjust rates of Ca 2+ uptake. This was accomplished by assessing the levels of gill ECaC mRNA and protein in fish exposed to treatments known to increase or decrease Ca 2+ uptake capacity. Exposure of trout to soft water (Ca 2+ = 20–30 nmol/l) for 5 days (a treatment known to increase Ca 2+ uptake capacity) caused a significant increase in ECaC mRNA levels and an increase in ECaC protein expression. The inducement of hypercalcemia by infusing fish with CaCl 2 (a treatment known to reduce Ca 2+ uptake) was associated with a significant decrease in ECaC mRNA levels, yet protein levels were unaltered. ECaC mRNA and protein expression were increased in fish treated with the hypercalcemic hormone cortisol. Finally, exposure of trout to 48 h of hypercapnia (∼7.5 mmHg, a treatment known to increase Ca 2+ uptake capacity) elicited an ∼100-fold increase in the levels of ECaC mRNA and a significant increase in protein expression. Immunocytochemical analysis of the gills from hypercapnic fish suggested a marked increase in the apical expression of ECaC on pavement cells and a subpopulation of mitochondria-rich cells. The results of this study provide evidence that Ca 2+ uptake rates are, in part, regulated by the numbers of apical membrane Ca 2+ channels that, in turn, modulate the inward flux of Ca 2+ into gill epithelial cells. transient receptor potential vanilloid 6; hypercapnia; cortisol; hypercalcemia; soft water Address for reprint requests and other correspondence: S. Perry, Dept. of Biology, Center for Advanced Research in Environmental Genomics, Univ. of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5 Canada (e-mail sfperry@science.uottawa.ca )

Journal

AJP - Regulatory, Integrative and Comparative PhysiologyThe American Physiological Society

Published: Nov 1, 2006

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