Figure 1.

No disparity in action potential-evoked poststimulation loading for FM1-43 and FM2-10. A, Granule neuron cultures were loaded with either FM1-43 or FM2-10 using trains of 200 (10 Hz), 400 (40 Hz), or 800 (80 Hz) action potentials. Dyes were loaded during stimulation at S1, but washout was delayed for 5 min at S2. Unloading was stimulated by 30 s stimuli of 50 mm KCl except for cultures loaded with 200 action potentials, for which two sequential trains of 400 action potentials (40 Hz) were used. B, C, Time course of the average response for nerve terminals loaded with either FM1-43 (B) or FM2-10 (C) during action potential stimulation at 80 Hz is displayed. D, Mean ΔS2/ΔS1 ratio ± SEM is displayed for each stimulation condition. All experiments were performed four times except those with 200 action potentials (n = 3). No significant difference between FM2-10 and FM1-43 loading was observed during any stimulation protocol (Student's t test).