Once internalized (in endocytosis), synaptic vesicles become reavailable for exocytosis in

Range ~30 sec
Organism Rat Rattus norvegicus
Reference Ryan TA et al., The kinetics of synaptic vesicle recycling measured at single presynaptic boutons. Neuron. 1993 Oct11(4):713-24. abstract & p.722 left column bottom paragraphPubMed ID8398156
Method Abstract: "[Investigators] used the fluorescent membrane probe FM 1-43 to label recycling synaptic vesicles within the presynaptic boutons of dissociated hippocampal neurons in culture. Quantitative time-lapse fluorescence imaging was employed in combination with rapid superfusion techniques to study the dynamics of synaptic vesicles within single boutons."
Comments Abstract: "[Investigators'] measurements indicate that under sustained membrane depolarization, endocytosis persists much longer than exocytosis, with a t1/2 approximately 60 s (approximately 24 degrees C) once internalized, vesicles become reavailable for exocytosis in approximately 30 s." P.722 left column bottom paragraph: "Conclusions and Outlook for Future Experiments: [Investigators’] data provide evidence that synaptic vesicles within presynaptic boutons of CNS [central nervous system] neurons are subject to recycling by a tightly coupled series of events (Figure 7). New information about the dynamics of the various steps may be summarized as follows. When boutons are challenged by a sustained membrane depolarization that evokes Ca2+ entry, a pool of synaptic vesicles fuse with the plasma membrane within a period of <15 s. Following exocytosis, they remain fused with the plasma membrane for a t1/2 of ~60 s before endocytosis takes place. They then undergo repriming, becoming reavailable for release with a t1/2 of <~30 s."
Entered by Uri M
ID 112763