ATP-dependent H+ transport by the turtle bladder: NBD-C1 preferentially inhibits the vanadate-insensitive component in isolated membranes.
We investigated the inhibitory effects of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) on ATP-dependent H+ accumulation by membrane vesicles prepared from the turtle urinary bladder epithelium. NBD-Cl at 30 microM was found to completely inhibit the vanadate-insensitive component of H+ transport, with half-maximal inhibition occurring at 4.2 to 5.4 microM. In contrast, the vanadate-inhibitable component was unaffected by 30 microM NBD-Cl. At high concentrations (300 microM), both components were fully inhibited. The results confirm the presence of two distinct H+ transport processes in turtle bladder membranes and identify selective inhibitors, NBD-Cl and vanadate, for each process.
Youmans
S J
SJ
Department of Medicine, East Carolina University School of Medicine, Greenville, NC 27858-4354.
Barry
C R
CR
D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D010069:Oxadiazoles / Q000494:pharmacology*; D011522:Protons; D014426:Turtles; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology*
D007473:Ion Channels; D010069:Oxadiazoles; D011522:Protons; D014638:Vanadates; D000255:Adenosine Triphosphate; D009327:4-Chloro-7-nitrobenzofurazan