The structural organization of the readily releasable pool of synaptic vesicles.
The defining morphological feature of chemical synapses is the vesicle cluster in the presynaptic nerve terminal. It has generally been assumed that vesicles closest to release sites are recruited first during nerve activity. We tested this by selectively labeling the "readily releasable" pool, those vesicles released first during physiological stimulation. The readily releasable vesicles were not clustered close to the presynaptic membrane but instead were dispersed almost randomly throughout the vesicle cluster. Thus, vesicles are not recruited according to proximity to release sites but are mobilized differently, perhaps by being peeled from the surface of the cluster.
Rizzoli
Silvio O
SO
Department of Physiology & Biophysics, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
Betz
William J
WJ
D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D004705:Endocytosis; D005089:Exocytosis; D005456:Fluorescent Dyes / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D009068:Movement; D009469:Neuromuscular Junction / Q000502:physiology* / Q000648:ultrastructure; D018377:Neurotransmitter Agents / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000502:physiology* / Q000648:ultrastructure; D011726:Pyridinium Compounds / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D011894:Rana pipiens; D013570:Synaptic Membranes / Q000502:physiology / Q000648:ultrastructure; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000502:physiology* / Q000648:ultrastructure
C073804:FM1 43; D005456:Fluorescent Dyes; D018377:Neurotransmitter Agents; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds