Figure 9.

Cdk5 is not required for endocytosis evoked by mild stimulation. A, FM1–43 was loaded using 200 action potentials delivered at 10 Hz and immediately washed away after termination of stimulation. Dye unloading was evoked by two sequential stimuli of 400 action potentials delivered at 40 Hz. Cultures were preincubated with 50 μm roscovitine (Rosco) for 10 min before and during all steps up to and including S2 loading. B, Cumulative histogram of the effect of roscovitine on dye loading in individual nerve terminals (ΔS2/ΔS1, n = 250, Ctrl; n = 322, Rosco). Closed symbols represent control (Ctrl) and gray symbols represent roscovitine. In all experiments, n = 3 for control and n = 4 for roscovitine.