Figure 7.

Antagonism of cdk5 inhibits uptake of FM1–43, but not FM2–10 during strong physiological stimulation. A, Cultures were loaded with either FM2–10 or FM1–43 using 800 action potentials delivered at 80 Hz. Dye was washed away immediately after stimulation. Unloading was stimulated with two sequential 30 s stimuli of 50 mm KCl. Cultures were preincubated with 50 μm roscovitine (Rosco) for 10 min before and during all steps up to and including S2 loading. B, C, Cumulative histograms of the effect of roscovitine on either FM2–10 (B) or FM1–43 (C) loading in individual nerve terminals are displayed (ΔS2/ΔS1, n = 356 control FM2–10; n = 141, Rosco FM2–10; n = 262, control FM1–43; n = 252, Rosco FM1–43). Open symbols, FM2–10; closed symbols, FM1–43; gray symbols, roscovitine. For all experiments, n = 3, except for n = 4 for FM1–43 Rosco.