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Synaptic vesicle dynamics in rat fast and slow motor nerve terminals

Lookup NU author(s): Emeritus Professor Clarke Slater

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Abstract

We have investigated whether rat motor nerve terminals with different in vivo activity patterns also have different vesicle trafficking characteristics. To do this, we monitored, using combined optical and electrical techniques, the rate of exocytosis (during different frequencies and patterns of activity), the releasable pool size, and the recycle time of synaptic vesicles in terminals on soleus (slow-twitch) and extensor digitorum longus [(EDL); fast-twitch] muscle fibers. EDL terminals had a higher initial quantal content (QC) than soleus, but during tonic or phasic stimulation at 20-80 Hz, EDL QC ran down to a greater extent than soleus QC. By recording loss of fluorescence from exocytosing vesicles labeled with the dye FM1-43, EDL terminals were found to destain faster than those in soleus. Simultaneous intracellular recording of end plate potentials, to count the number of vesicles released, permitted estimation of the total vesicle pool (VP) size and the recycle time by combining the optical and electrophysiological data. Soleus vesicle pool was larger than EDL, but recycle time was not significantly different. These terminals, therefore, are adapted to their in vivo activity patterns by alterations in QC and VP size but not recycle time.


Publication metadata

Author(s): Reid B, Slater CR, Bewick GS

Publication type: Article

Publication status: Published

Journal: Journal of Neuroscience

Year: 1999

Volume: 19

Issue: 7

Pages: 2511-2521

Print publication date: 01/04/1999

ISSN (print): 0270-6474

ISSN (electronic): 1529-2401

Publisher: Society for Neuroscience

PubMed id: 10087065


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