The volume-activated chloride current in human endothelial cells depends on intracellular ATP.
We have studied the effect of intracellular ATP on volume-activated CI(-)-currents in endothelial cells from human umbilical veins by means of the whole-cell patch-clamp technique. The run-down of this current in ruptured patches during repetitive applications of hypotonic solutions (HTS) could be significantly reduced if the cells were internally perfused with a pipette solution that contained 4 mmol/l ATP. This run-down was much less pronounced if currents were recorded using nystatin-perforated patches. The amplitude of the current was drastically reduced and its activation became slower if the cells were superfused with a glucose-free medium with 1 mmol/l KCN. Adding 4 mmol/l ATP gamma S, a poorly hydrolyzable ATP-analogue, to the patch pipette prevented run-down of the current during repetitive activations by HTS, even if the cells were superfused with glucose-free solution with 1 mmol/l KCN. It is concluded that activation of the mechanosensitive Cl- conductance in human endothelial cells requires the presence of intracellular ATP, but not its hydrolysis.
Oike
M
M
K. U. Leuven, Laboratorium voor Fysiologie, Belgium.
Droogmans
G
G
Nilius
B
B
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D002712:Chlorides / Q000502:physiology*; D004553:Electric Conductivity; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism*; D011190:Potassium Cyanide / Q000494:pharmacology
D002712:Chlorides; D007038:Hypotonic Solutions; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D011190:Potassium Cyanide