抄録
We examined patch clamp recordings in murine macrophage-like J774-A.1 cells after the uptake of IgG-opsonized latex beads. First, we prepared isolated phagosomes from the macrophages by cutting the plasma membrane with a sharp glass pipette. Single channel recordings of the isolated phagosomes revealed that large conductance (230pS) chloride selective channels were present in the phagosomes. These channels had the characteristics of the current frequenty observed in excised patches of the plasma membranes (but very rarely in whole-cell recordings). Second, we combined whole-cell capacitance and volage-clamp recordings to evaluate phagosome membrane potentials. Exocyotis of the phagosomes by the activation of G proteins were measured in the capacitance step and transient current. We found that phagosomes have lumen negative membrane potentials. In some cases, 200-300pS channels emerged immediate after the capacitance steps, showing that large conductance chlolide channels were incorporated to the cell membrane. These data indicate that large conductance chloride channels regulate the membrane potentials of the phagosomes in macrophages. [J Physiol Sci. 2007;57 Suppl:S233]
