Evidence for a chloride conductance in secretory membrane of parietal cells.
A fluorescence-quench method using acridine orange as the probe was employed to monitor acid formation in situ by detergent-permeabilized gastric glands. In KCl medium, the addition of ATP to the permeabilized glands resulted in a rapid decrease in fluorescence and addition of valinomycin resulted in a second phase of fluorescence quench. The fluorescence was restored by addition of the H+-K+-ATPase inhibitor, Sch 28080. An ATP-dependent fluorescence quench was observed also in K2SO4 or K+-isethionate medium; however, valinomycin was ineffective in the Cl-free media. The ATP-dependent quench could be reversed or prevented by the electrogenic protonophore, tetrachlorosalicylanilide (TCS), in KCl medium but not in Cl-free media. The results with TCS are interpreted as demonstrating a large Cl- conductance in the secretory membrane, whereas the results with valinomycin indicate that resting membranes lack a K+ conductance. The data suggest that a complex KCl pathway that may demonstrate a Cl- conductance is used to activate acid secretion.
Perez
A
A
Department of Physiology, Emory University, Atlanta, Georgia 30322.
Blissard
D
D
Sachs
G
G
Hersey
S J
SJ
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D018118:Chloride Channels; D002712:Chlorides / Q000502:physiology*; D005753:Gastric Mucosa / Q000502:physiology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008565:Membrane Proteins / Q000502:physiology*; D008962:Models, Theoretical; D010295:Parietal Cells, Gastric / Q000502:physiology*; D011817:Rabbits; D012458:Salicylanilides / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D014634:Valinomycin / Q000494:pharmacology
D000897:Anti-Ulcer Agents; D018118:Chloride Channels; D002712:Chlorides; D007093:Imidazoles; D007473:Ion Channels; D008565:Membrane Proteins; D012458:Salicylanilides; C035235:Sch 28080; D014634:Valinomycin; C003390:3,3',4',5-tetrachlorosalicylanilide