Figure 11.
Inhibition of slow endocytosis results in elimination of a sustained phase of SV exocytosis. A, Two parameters were monitored with respect to dye unloading, the time for nerve terminals to lose 50% of their dye content (t1/2, shown in dark gray) and the time for the remainder to be unloaded (Tail, shown in light gray). In all experiments, dye was loaded with 50 mm KCl and washed away immediately after stimulation as in Figure 1A. Dye was unloaded with 50 mm KCl. Cultures were preincubated with either 10 μm CsA before and during S2 loading or 50 μm Rosco at all steps including S2 loading. B, Effect of CsA and roscovitine (Rosco) on the time taken to unload the initial 50% of dye content (t1/2). C, Effect of CsA and Rosco on the time taken to unload the remainder of dye (Tail). Data are presented as either t1/2 or tail kinetics at S2 normalized to the internal S1 control (n = 6 experiments for FM2–10 CsA; n = 3 for FM2–10 Rosco; n = 4 for FM1–43 CsA; n = 3 for FM1–43 Rosco; all data are ±SEM; Student's t test, **p < 0.01).