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In Situ Visualization of Axon Growth and Growth Cone Dynamics in Acute Ex Vivo Embryonic Brain Slice Cultures
Published on: October 14, 2021
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Spatial temperature gradients guide axonal outgrowth.
Bryan Black1, Vivek Vishwakarma2, Kamal Dhakal1
1Biophysics and Physiology Lab, Department of Physics, USA.
Scientific Reports
|July 28, 2016
Summary
Physical cues, like laser-induced temperature fields, guide axonal pathfinding. Near-infrared lasers create repulsive guidance by activating temperature-sensitive receptors and calcium influx, crucial for neural development and regeneration.
Area of Science:
- Neuroscience
- Biophysics
- Cell Biology
Background:
- Axonal pathfinding is vital for neural network formation during development and regeneration.
- Chemical cues are traditionally considered primary drivers of axonal guidance.
- Emerging evidence highlights the significant role of physical cues in axonal navigation.
Purpose of the Study:
- To investigate the detailed mechanism by which physical cues guide axonal pathfinding.
- To explore the repulsive guidance effect of near-infrared laser microbeams on advancing axons.
- To elucidate the photothermal mechanisms underlying laser-induced axonal guidance.
Main Methods:
- Utilized weakly-focused near-infrared continuous wave (CW) laser microbeams to perturb axonal paths.
- Investigated the influence of laser wavelength and power on axonal guidance.
- Assessed the role of temperature gradients, extracellular calcium, and TRPV1 channels in guidance.
Main Results:
- Near-infrared laser beams act as effective repulsive guidance cues for axons.
- Guidance is mediated by a laser-induced temperature field activating temperature-sensitive membrane receptors and calcium influx.
- Lower threshold laser power was required in the near-infrared compared to the visible spectrum due to increased light absorption.
Conclusions:
- Photothermal effects, specifically shallow temperature gradients, are responsible for laser-induced axonal guidance.
- Temperature-sensitive membrane receptors and calcium influx play a critical role in this repulsive guidance mechanism.
- This study reveals a novel physical mechanism for axonal guidance, distinct from traditional chemical cues.
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