Volume-sensitive chloride channels do not mediate activation-induced chloride efflux in human neutrophils.
Many agents that activate neutrophils, enabling them to adhere to venular walls at sites of inflammation, cause a rapid Cl(-) efflux. This Cl(-) efflux and the increase in the number and affinity of beta(2) integrin surface adhesion molecules (up-regulation) are all inhibited by ethacrynic acid and certain aminomethyl phenols. The effectiveness of the latter compounds correlates with their inhibition of swelling-activated Cl(-) channels (I(Clvol)), suggesting that I(Clvol) mediates the activator-induced Cl(-) efflux. To test this hypothesis, we used whole-cell patch clamp in hypotonic media to examine the effects of inhibitors of up-regulation on I(Clvol) in neutrophils and promyelocytic leukemic HL-60 cells. Both the channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid and [3-methyl-1-p-sulfophenyl-5-pyrazolone-(4)]-[1,3-dibutylbarbituric acid]-pentamethine oxonol (WW781), a nonpenetrating oxonol, inhibited I(Clvol) at concentrations similar to those that inhibit beta(2) integrin up-regulation. However, ethacrynic acid, at the same concentration that inhibits activator-induced Cl(-) efflux and up-regulation, had no effect on I(Clvol) and swelling-activated Cl(-) efflux, providing evidence against the involvement of I(Clvol) in the activator-induced Cl(-) efflux.
Perez-Cornejo
Patricia
P
Department of Biochemistry and Biophysics, School of Medicine, Aab Institute of Biomedical Sciences, University of Rochester, Rochester, NY 14642, USA.
Arreola
Jorge
J
Law
Foon-Yee
FY
Schultz
Joanne B
JB
Knauf
Philip A
PA
D001557:Benzenesulfonates / Q000494:pharmacology; D018821:CD18 Antigens / Q000097:blood; D018118:Chloride Channels / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism*; D004976:Ethacrynic Acid / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D018375:Neutrophil Activation; D009504:Neutrophils / Q000737:chemistry / Q000378:metabolism*; D009579:Nitrobenzoates / Q000494:pharmacology
D001557:Benzenesulfonates; D018821:CD18 Antigens; D018118:Chloride Channels; D002712:Chlorides; D009579:Nitrobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; C031916:WW-781; D004976:Ethacrynic Acid