Activation of single Ca2(+)-dependent K+ channel by external ATP in mouse macrophages.
Single Ca2(+)-dependent K+ currents responding to external ATP were recorded from cell-attached patches on mouse peritoneal macrophages. Extracellularly applied ATP activated an inward single-channel current with a conductance of 25 pS and a reversal potential of -79 mV (pipette potential, Vp) when the pipette contained a 145 mM KCl solution. The reversal potential was shifted 56 mV positive by a 10-fold reduction in external (pipette) K+ concentration. The effect of ATP was abolished by either removal of external Ca2+ or treatment with an intracellular Ca2+ chelator, the acetoxymethyl ester of 1,2-bis (2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid (BAPTA-AM). This channel has a mean open time of 9.1 ms and open probability was not strongly dependent on Vp in the range tested (+120 to -30 mV).
Hara
N
N
Department of Physiology, Shimane Medical University, Izumo, Japan.
Ichinose
M
M
Sawada
M
M
Imai
K
K
Maeno
T
T
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology / Q000031:analogs & derivatives; D004553:Electric Conductivity; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D015640:Ion Channel Gating; D008264:Macrophages / Q000187:drug effects*; D051379:Mice; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology
D002614:Chelating Agents; D015221:Potassium Channels; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium