Zn(2+) is effective in the treatment of acute diarrhea, but its mechanisms are not completely understood. We previously demonstrated that Zn(2+) inhibits the secretory effect of cyclic adenosine monophosphate but not of cyclic guanosine monophosphate in human enterocytes. The aim of the present study was to investigate whether Zn(2+) inhibits intestinal ion secretion mediated by the Ca(2+) or nitric oxide pathways. To investigate ion transport we evaluated the effect of Zn(2+) (35 microM) on electrical parameters of human intestinal epithelial cell monolayers (Caco2 cells) mounted in Ussing chambers and exposed to ligands that selectively increased intracellular Ca(2+) (carbachol 10(-6)M) or nitric oxide (interferon-gamma 300 UI/ml) concentrations. We also measured intracellular Ca(2+) and nitric oxide concentrations. Zn(2+) significantly reduced ion secretion elicited by carbachol (-87%) or by interferon-gamma (-100%), and inhibited the increase of intracellular Ca(2+) and nitric oxide concentrations. These data indicate that Zn(2+) inhibits ion secretion elicited by Ca(2+) and nitric oxide by directly interacting with the enterocyte. They also suggest that Zn(2+) interferes with three of the four main intracellular pathways of intestinal ion secretion that are involved in acute diarrhea.

Zinc inhibits calcium-mediated and nitric oxide-mediated ion secretion in human enterocytes

CANZONIERO L. M.;
2010

Abstract

Zn(2+) is effective in the treatment of acute diarrhea, but its mechanisms are not completely understood. We previously demonstrated that Zn(2+) inhibits the secretory effect of cyclic adenosine monophosphate but not of cyclic guanosine monophosphate in human enterocytes. The aim of the present study was to investigate whether Zn(2+) inhibits intestinal ion secretion mediated by the Ca(2+) or nitric oxide pathways. To investigate ion transport we evaluated the effect of Zn(2+) (35 microM) on electrical parameters of human intestinal epithelial cell monolayers (Caco2 cells) mounted in Ussing chambers and exposed to ligands that selectively increased intracellular Ca(2+) (carbachol 10(-6)M) or nitric oxide (interferon-gamma 300 UI/ml) concentrations. We also measured intracellular Ca(2+) and nitric oxide concentrations. Zn(2+) significantly reduced ion secretion elicited by carbachol (-87%) or by interferon-gamma (-100%), and inhibited the increase of intracellular Ca(2+) and nitric oxide concentrations. These data indicate that Zn(2+) inhibits ion secretion elicited by Ca(2+) and nitric oxide by directly interacting with the enterocyte. They also suggest that Zn(2+) interferes with three of the four main intracellular pathways of intestinal ion secretion that are involved in acute diarrhea.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12070/4266
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