Figure 2.

BK raises [Ca²⁺]_i to inhibit M current. Simultaneous recordings of [Ca²⁺]_i and M current were done in a neuron loaded with indo-1 dye through the patch pipette (0.1 mM BAPTA/0.1 mM indo-1). In this neuron, BK raised [Ca²⁺]_i (continuous trace) from 105 nM to 218 nM. The dashed line is the basal [Ca²⁺]_i level. For comparison, the M current data (circles) were inverted (vertical bar) and aligned to match the amplitude of the [Ca²⁺]_i signal.