Mechanical tension contributes to clustering of neurotransmitter vesicles at presynaptic terminals

Scott Siechen, Shengyuan Yang, Akira Chiba, Taher Saif

Research output: Contribution to journalArticlepeer-review

119 Scopus citations


Memory and learning in animals are mediated by neurotransmitters that are released from vesicles clustered at the synapse. As a synapse is used more frequently, its neurotransmission efficiency increases, partly because of increased vesicle clustering in the presynaptic neuron. Vesicle clustering has been believed to result primarily from biochemical signaling processes that require the connectivity of the presynaptic terminal with the cell body, the central nervous system, and the postsynaptic cell. Our in vivo experiments on the embryonic Drosophila nervous system show that vesicle clustering at the neuromuscular presynaptic terminal depends on mechanical tension within the axons. Vesicle clustering vanishes upon severing the axon from the cell body, but is restored when mechanical tension is applied to the severed end of the axon. Clustering increases when intact axons are stretched mechanically by pulling the postsynaptic muscle. Using micro mechanical force sensors, we find that embryonic axons that have formed neuromuscular junctions maintain a rest tension of ≈1 nanonewton. If the rest tension is perturbed mechanically, axons restore the rest tension either by relaxing or by contracting over a period of ≈15 min. Our results suggest that neuromuscular synapses employ mechanical tension as a signal to modulate vesicle accumulation and synaptic plasticity.

Original languageEnglish (US)
Pages (from-to)12611-12616
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number31
StatePublished - Aug 4 2009


  • MEMS
  • Neuron
  • Synapse
  • Synaptic vesicle

ASJC Scopus subject areas

  • General


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