| 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." |