Figure 3. Application of the cell-permeant Ca²⁺ chelator, BAPTA-AM, activates inward channel currents that have similar properties to the CPA- and caffeine-evoked channel currents.

A, activation of inward channel currents at negative membrane potentials after bath application of BAPTA-AM for ∼20 min. Note that no channel currents could be observed at positive membrane potentials. B, the I–V relationship of the channel currents shown in A. The channel currents had a slope conductance of 2.3 pS between −120 and −40 mV and an extrapolated E_r (↓) of +25 mV.