A heterogeneous electrophysiological profile of bone marrow-derived mast cells.
Electrophysiological properties of mouse bone marrow-derived mast cells (BMMC) were studied under the whole-cell clamp configuration. About one third of the cells were quiescent, but others expressed either inward or outward currents. Inwardly rectifying (IR) currents were predominant in 14% of the cells, and outwardly rectifying (OR) currents in 24%. The rest (22%) of the cells exhibited both inward and outward currents. The IR currents were eliminated by 1 mM Ba2+, and were partially inhibited by 100 microM quinidine. The reversal potential was dependent on extracellular K+, thereby indicating that K+ mediated the IR currents. The negative conductance region was seen at potentials positive to EK. The OR currents did not apparently depend on the extracellular K+ concentration, but were reduced by lowering the extracellular Cl- concentration. The OR currents were partially blocked by 1 mM Ba2+, and were further blocked by a Cl- channel blocker, 4,4'-diisothiocyano-2,2'-stilbenedisulfonate (DIDS). In addition, the reversal potential of the OR currents was positively shifted by decreasing the ratio of external and internal Cl- concentrations, suggesting that Cl- was a major ion carrier. In cells exhibiting IR currents, the membrane potential varied among cells and tended to depolarize by elevating the external K+ concentration. In cells with OR currents, the resting potential was hyperpolarized in association with an increase in conductance.(ABSTRACT TRUNCATED AT 250 WORDS)
Kuno
M
M
Department of Physiology, Osaka City University, Medical School, Japan.
Shibata
T
T
Kawawaki
J
J
Kyogoku
I
I
D000818:Animals; D001854:Bone Marrow Cells; D002462:Cell Membrane / Q000502:physiology; D004594:Electrophysiology; D017136:Ion Transport; D008297:Male; D008407:Mast Cells / Q000502:physiology*; D008564:Membrane Potentials; D051379:Mice; D008807:Mice, Inbred BALB C