J Korean Med Sci.  1994 Dec;9(6):497-504. 10.3346/jkms.1994.9.6.497.

Stimulation of Cl- secretion by AlF4- and vanadate in T84 cells

• Hwang TH
• Jung JS
• Bae HR
• Yun I
• Lee SH

• KMID: 644842
• DOI: http://doi.org/10.3346/jkms.1994.9.6.497

Abstract

We investigated the mechanism of Cl- secretion by fluoroaluminate(AlF4-) and sodium orthovanadate(vanadate) using the human colonic T84 cell line. T84 cell monolayers grown on collagen-coated filters were mounted in Ussing chambers to measure short circuit current(ISC). Serosal addition of AlF4- or vanadate to T84 monolayers produced a sustained increase in ISC. Removal of Ca2+ from the serosal bathing solution partially inhibited AlF4-(-)and vanadate-induced ISC, and readministration of Ca2+ restored AlF4-(-)and vanadate-induced ISC. Carbachol application in the presence of forskolin, AlF4- or vanadate induced a synergistic increase of ISC. Forskolin and vanadate significantly increased cellular cAMP level, while carbachol and AlF4- did not. Carbachol, AlF4- and vanadate significantly increased [Ca2+]i. After Na+ in mucosal bathing solution was replaced with K+, and the mucosal membrane of T84 cell was permeabilized with amphotericin B, AlF4-, vanadate, and carbachol increased K+ conductance, but forskolin did not. After sodium chloride in serosal bathing solution was replaced with sodium gluconate and the serosal membrane was permeabilized with nystatin, forskolin, AlF4-, and vanadate increased Cl- conductance, but carbachol did not. AlF4-(-)induced ISC was remarkably inhibited by the pretreatment of pertussis toxin(2 micrograms/ml) for 2 hours. These results indicate that AlF4- and vanadate can increase Cl- secretion via simultaneous stimulation of Cl- channel and K+ channel in T84 cells. However, the AlF4- action is mostly attributed to stimulation of pertussis toxin-sensitive G-proteins, whereas the vanadate action mostly results from G protein-independent mechanisms.

Keyword

Cl- secretion; AIF4-; Vanadate; T84 cells

MeSH Terms

Aluminum/*pharmacology
Amphotericin B/pharmacology
Carbachol/pharmacology
Cell Polarity
Cells, Cultured/drug effects
Chloride Channels/drug effects/*physiology
Chlorides/*physiology
Colon
Electrophysiology
Fluorine/*pharmacology
Forskolin/pharmacology
GTP-Binding Proteins/physiology
Human
Pertussis Toxin
Potassium/pharmacology
Potassium Channels/drug effects/physiology
Second Messenger Systems
Signal Transduction
Support, Non-U.S. Gov't
Vanadates/*pharmacology
Virulence Factors, Bordetella/pharmacology