Nav: Home

Using water molecules to unlock neurons' secrets

December 11, 2018

Neurons are brain cells that communicate with each other by sending electrochemical signals along axons. When a neuron is about to release a signal - in the form of an electric charge - it allows ions to pass through its membrane via ion channels. This ion transfer creates an electrical potential difference between the inside and outside of the cell, and that difference is referred to as the membrane potential.

A team of researchers at the Laboratory for fundamental BioPhotonics (LBP) within EPFL's School of Engineering (STI) has come up with a way to monitor changes in membrane potential and to observe ion fluxes by studying the behavior of the water molecules surrounding the membranes of the neurons. The researchers, who successfully tested their method on in vitro mouse neurons, have just published their findings in Nature Communications.

No more electrodes or fluorophores

A better understanding of the electrical activity of neurons could provide insight into a number of processes taking place in our brains. For example, scientists could see whether a neuron is active or resting, or if it is responding to drug treatment. Up until now, the only way to monitor neurons was by injecting fluorophores into, or attaching electrodes onto, the part of the brain being studied - but fluorophores can be toxic, and electrodes can damage the neurons.

Recently, the LBP researchers developed a way of tracking electrical activity in neurons simply by looking at the interactions between water molecules and the neural membranes. "Neurons are surrounded by water molecules, which change orientation in the presence of an electric charge," says Sylvie Roke, director of the LBP. "When the membrane potential changes, the water molecules will re-orient - and we can observe that."

In their study, the researchers altered the neuronal membrane potential by subjecting the neurons to a rapid influx of potassium ions. This caused the ion channels on the neurons' surface - which serve to regulate the membrane potential - to open and let the ions through. The researchers then turned off the flow of ions, and the neurons released the ions that they had picked up.

In order to monitor this activity, the researchers probed the hydrated neuronal lipid membranes by illuminating the cells with two laser beams of the same frequency. These beams consist of femtosecond laser pulses -using technology for which the 2018 Nobel prize in physics was awarded- so that the water molecules on the interface of the membrane generate photons with a different frequency, known as second-harmonic light.

"We see both fundamental and applied implications of our research. Not only can it help us understand the mechanisms that the brain uses to send information, but it could also appeal to pharmaceutical companies interested in in vitro product testing," adds Roke. "And we have now shown that we can analyze a single neuron or any number of neurons at a time."
-end-
Reference: M. E. P. Didier, O. B. Tarun, P. Jourdain, P. Magistretti, and S. Roke, "Membrane water for probing neuronal membrane potentials and ionic fluxes at the single cell level," Nature Communications.

Julia Jacobi Chair of Photomedicine - Laboratory for fundamental BioPhotonics

Ecole Polytechnique Fédérale de Lausanne

Related Neurons Articles:

How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Astrocytes protect neurons from toxic buildup
Neurons off-load toxic by-products to astrocytes, which process and recycle them.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
The salt-craving neurons
Pass the potato chips, please! New research discovers neural circuits that regulate craving and satiation for salty tastes.
When neurons are out of shape, antidepressants may not work
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medication for major depressive disorder (MDD), yet scientists still do not understand why the treatment does not work in nearly thirty percent of patients with MDD.
Losing neurons can sometimes not be that bad
Current thinking about Alzheimer's disease is that neuronal cell death in the brain is to blame for the cognitive havoc caused by the disease.
Neurons that fire together, don't always wire together
As the adage goes 'neurons that fire together, wire together,' but a new paper published today in Neuron demonstrates that, in addition to response similarity, projection target also constrains local connectivity.
Scientists accidentally reprogram mature mouse GABA neurons into dopaminergic-like neurons
Attempting to make dopamine-producing neurons out of glial cells in mouse brains, a group of researchers instead converted mature inhibitory neurons into dopaminergic cells.
More Neurons News and Neurons Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab