PIP 5-kinase is faster than PI 4-kinase. Tail current amplitudes were used to measure current inhibition by Dr-VSP or M₁R activation and its recovery. (A) Time course of tail current amplitude in a cell transfected with Dr-VSP and KCNQ2/3 (2 points s⁻¹). (B) Superimposed currents at time points before VSP activation (a), after VSP activation (b), and during recovery (c). (C) Summary of tail current amplitudes relative to baseline after VSP activation (b/a) and after recovery (c/a). (D) Time constant of a single-exponential fit to the recovery time course (time b to c). (C and D) Summaries of 19 cells. (E) Time course of tail current amplitudes in a cell transfected with M₁R and KCNQ2/3 (1 point s⁻¹). (F) Superimposed currents at time points a, b, and c indicated in E. (G) Tail current inhibition by M₁R activation (summary of 10 cells). (H) Time constant of an exponential fit of recovery (summary of seven cells).