Figure 5.
Syntabulin promotes recovery from synaptic vesicle depletion. Presynaptic neurons were transfected with STB-siRNA or con-siRNA (A, B), and GFP-KBD or GFP (C, D). A, C, EPSPs were recorded at 1 Hz. A 4 min train of action potentials at 5 Hz was applied, as indicated, to deplete releasable synaptic vesicles at presynaptic terminals. EPSP amplitudes (amp) were normalized to the averaged EPSP amplitude measured for 1 min before application of the train. Normalized values (circles) were plotted with the smoothed lines (green, gray, and blue) using an 8 point-moving average algorithm. EPSP amplitude recovered with two different rates: a first fast phase (red arrow) and then a slow phase (orange arrow), after the cessation of synaptic vesicle depletion. The slow recovery phase can be fit with a linear line (cyan and pink). B, D, Mean EPSP amplitudes shown in A, C are plotted with SEM at 1 min intervals. The number of experiments is indicated in parentheses. *p < 0.05; unpaired Student's t test.