Nav: Home

Better learning through zinc?

March 21, 2017

Zinc is a vital micronutrient involved in many cellular processes: For example, in learning and memory processes, it plays a role that is not yet understood. By using nanoelectrochemical measurements, Swedish researchers have made progress toward understanding by demonstrating that zinc influences the release of messenger molecules. As reported in the journal Angewandte Chemie, zinc changes the number of messenger molecules stored in vesicles and the dynamics of their release from the cell.

When signals are transmitted by synapses, messenger molecules (neurotransmitters) are released from storage chambers (synaptic vesicles) into the synaptic cleft, where they are "recognized" by neighboring nerve cells. This release is based on exocytosis: The vesicle docks at the cell membrane, opens at the point of contact, releases part of its contents to the outside, closes, and separates from the plasma membrane so it can be refilled.

A team led by Andrew G. Ewing at Gothenburg University, Sweden, used carbon fiber electrodes with nanotips to study the influence of zinc on these processes. They carried out measurements on PC12 cells that release the neurotransmitter dopamine when stimulated by a high potassium concentration, analogous to nerve cells. "By applying an electrode tip to the surface of the cell, we can follow the opening of an individual vesicle and compute the number of molecules released," says Ewing. In contrast, if the tip of the electrode is inserted into the cell, the vesicles in the cytoplasm stick to the electrode and release their full contents. Says Ewing: "The current transients allow us to determine how many transmitter molecules are contained in individual vesicles directly in the cytoplasm of the living cells."

After treatment with zinc, the total number of neurotransmitters contained in vesicles was reduced, on average by 27%. However, the amount of transmitter released upon stimulation remained constant. Analysis of the current transients provided an explanation of this apparent contradiction. According to Ewing, "Zinc changes the dynamics of the release. Before and after the opening of the vesicle a pore forms at the point of contact with the plasma membrane. After treatment with zinc, the pore closes more slowly than usual. The vesicle thus stays open longer and releases 92 % of its transmitter molecules to the outside--instead of only 66 % without the zinc."

In order to investigate this phenomenon more closely, the cells were stripped down layer by layer from the outside in and were analyzed by mass spectrometry. The researchers found one zinc species near the cell membrane and a second in the interior of the cell. "The former is capable of binding to protein kinase C, an enzyme that binds to the membrane to regulate the speed of exocytosis. The zinc species inside the cell could slow down the transport protein that loads the dopamine into the vesicles," suggests Ewing. "Our results finally provide a connection between zinc and the regulation of neurotransmitter release. This could be important for the formation and storage of memories."
-end-
About the Author

Dr. Ewing is Professor at both University of Gothenburg and Chalmers University of Technology. His team develops new chemical analysis methods for single cells and vesicles to understand the function of the brain. A particular goal, with collaborators Lin Ren and Per Malmberg on this work, is to understand the chemical mechanisms driving the initiation of short-term memory. He is an elected member of the Swedish Academy of Sciences, Chemistry Class (Nobel Class).https://www.chalmers.se/en/staff/Pages/andrew-ewing.aspx

Wiley

Related Nerve Cells Articles:

Unique fingerprint: What makes nerve cells unmistakable?
Protein variations that result from the process of alternative splicing control the identity and function of nerve cells in the brain.
Ragweed compounds could protect nerve cells from Alzheimer's
As spring arrives in the northern hemisphere, many people are cursing ragweed, a primary culprit in seasonal allergies.
Fooling nerve cells into acting normal
In a new study, scientists at the University of Missouri have discovered that a neuron's own electrical signal, or voltage, can indicate whether the neuron is functioning normally.
How nerve cells control misfolded proteins
Researchers have identified a protein complex that marks misfolded proteins, stops them from interacting with other proteins in the cell and directs them towards disposal.
The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.
Research confirms nerve cells made from skin cells are a valid lab model for studying disease
Researchers from the Salk Institute, along with collaborators at Stanford University and Baylor College of Medicine, have shown that cells from mice that have been induced to grow into nerve cells using a previously published method have molecular signatures matching neurons that developed naturally in the brain.
Bees can count with just four nerve cells in their brains
Bees can solve seemingly clever counting tasks with very small numbers of nerve cells in their brains, according to researchers at Queen Mary University of London.
Nerve cells in the human brain can 'count'
How do we know if we're looking at three apples or four?
How rabies virus moves through nerve cells, and how it might be stopped
Researchers found that the rabies virus travels through neurons differently than other neuron-invading viruses, and that its journey can be stopped by a drug commonly used to treat amoebic dysentery.
Direct conversion of non-neuronal cells into nerve cells
Researchers of the Mainz University Medical Center discovered that on the way to becoming neurons pericytes need to go through a neural stem cell-like state.
More Nerve Cells News and Nerve Cells Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.