Figure 2.

The dual cycle. At least two entities need recycling: The release site (shown in detail in Figure 1) and vesicles. Regarding vesicles three additional steps must be considered. (1) Endocytosis, which takes several seconds in patch clamped calyces and hippocampal cultures. (2) Vesicle recycling: 10 s of seconds (3) Vesicle docking and priming. It is proposed (Neher and Sakaba, 2008; Hosoi et al., 2009) that vesicle docking and priming actually occurs very rapidly (within 100–200 ms) once a release site has been cleared and that site clearing is slow (200 ms to 10 s), being modulated by (Ca²⁺) and other signaling pathways.