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Updated: Oct 29, 2025
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Measuring Synaptic Vesicle Endocytosis in Cultured Hippocampal Neurons
Published on: September 4, 2017
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Axon terminals control endolysosome diffusion to support synaptic remodelling.
Beatrice Terni1,2, Artur Llobet3,2
1Department of Pathology and Experimental Therapy, School of Medicine, Institute of Neurosciences, University of Barcelona, Barcelona, Spain beatriceterni@ub.edu.
Life Science Alliance
|July 6, 2021
Summary
Presynaptic endolysosomes, crucial for neuron health, become more mobile during synaptic remodeling. This increased mobility supports local degradation but impairs olfactory sensory neuron function in tadpoles.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Endolysosomes are acidic organelles vital for presynaptic protein homeostasis and synaptic stability.
- Their mobility is typically restricted by F-actin in axon terminals.
Purpose of the Study:
- To investigate the mobility of endolysosomes in olfactory sensory neuron axon terminals of Xenopus tropicalis tadpoles.
- To determine the role of F-actin and secreted protein acidic and rich in cysteine (SPARC) in regulating endolysosome dynamics.
Main Methods:
- Live imaging of endolysosome mobility in Xenopus tadpole olfactory sensory neurons.
- Local injection of SPARC to observe its effects on F-actin and endolysosome behavior.
- Assessment of tadpole olfactory behavior.
Main Results:
- F-actin restricts endolysosome diffusion with a coefficient of 6.7 × 10^-3 μm^2·s^-1.
- SPARC injection disrupts F-actin, increasing endolysosome presence and mobility within axon terminals.
- Enhanced endolysosome mobility did not lead to retrograde transport but correlated with impaired odorant detection.
Conclusions:
- Synaptic remodeling increases presynaptic endolysosome diffusion to support local degradative functions.
- SPARC-mediated synaptic changes impact endolysosome dynamics and olfactory sensory neuron function.
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