Figure 13.
Average time course of NT secretion after neutralization of intragranular pH with monensin. A-D, Hippocampal neurons expressing the different GFP-tagged NTs were treated as in Figure 9. Monensin (4 μm)-induced fluorescence increase and acceleration of the time course of release during subsequent depolarization was observed for all NTs (compare Fig. 11). The τ values represent the results of monoexponential fit curves for n ≥ 4 cells for each NT. E, Normalized average depolarization induced (50 mm K+) fluorescence decrease for indicated NTs after preincubation with monensin and for FM4-64 destaining of synaptic vesicles, respectively. The vertical line indicates start of depolarization. Average over n ≥ 4 cells for each condition. F, The boxed area in E at an expanded time scale. Note the similar half decay times (gray circles) for all NTs under these conditions but the still markedly faster speed of FM4-64 release from synaptic vesicles. Stimul., Stimulation. Error bars represent SEs.