Figure 3. Whole-cell currents in neutrophil granulocytes induced by low ADPR concentrations and the effects of intracellular Ca²⁺.

The pipette solution contained ADPR (5 or 1 μM) in the experiments shown in (A, B) and was free of ADPR in (C). The intracellular (pipette) Ca²⁺ concentration was low (<10 nM) in (A) and high (1 μM) in (B, C). The holding potential was −60 mV. The Na⁺ in the bath was replaced by the impermeable cation NMDG during time periods indicated by horizontal bars. The enlarged current tracings in the insets of (A, B) (scale bars, 5 pA and 10 s respectively) show single-channel openings resolved at low whole-cell current amplitudes.