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:

How hearing loss can change the way nerve cells are wired
Even short-term blockages in hearing can lead to remarkable changes in the auditory system, altering the behavior and structure of nerve cells that relay information from the ear to the brain, according to a new University at Buffalo study.
Lab-grown nerve cells make heart cells throb
Researchers at Johns Hopkins report that a type of lab-grown human nerve cells can partner with heart muscle cells to stimulate contractions.
Nerve-insulating cells more diverse than previously thought
Oligodendrocytes, a type of brain cell that plays a crucial role in diseases such as multiple sclerosis, are more diverse than have previously been thought, according to a new study by researchers at Karolinska Institutet in Sweden.
Aggregated protein in nerve cells can cause ALS
Persons with the serious disorder ALS, can have a genetic mutation that causes the protein SOD1 to aggregate in motor neurons in the brain and spinal cord.
Aggression causes new nerve cells to be generated in the brain
A group of neurobiologists from Russia and the USA, including Dmitry Smagin, Tatyana Michurina, and Grigori Enikolopov from Moscow Institute of Physics and Technology, have proven experimentally that aggression has an influence on the production of new nerve cells in the brain.
Researchers grow retinal nerve cells in the lab
Johns Hopkins researchers have developed a method to efficiently turn human stem cells into retinal ganglion cells, the type of nerve cells located within the retina that transmit visual signals from the eye to the brain.
Nerve cells warn brain of damage to the inner ear
Some nerve cells in the inner ear can signal tissue damage in a way similar to pain-sensing nerve cells in the body, according to new research from Johns Hopkins.
It takes a lot of nerve: Scientists make cells to aid peripheral nerve repair
Peripheral nerve injuries, such as those resulting from neuropathies, physical trauma or surgery, are common and can cause partial or complete loss of nerve function and a reduced quality of life.
Nerve cells use each other as maps
When nerve cells form in an embryo they have to be guided to their final position by navigating a kind of molecular and cellular 'map' in order to function properly.
What hundreds of biomolecules tell us about our nerve cells
Researchers at the Luxembourg Centre for Systems Biomedicine, of the University of Luxembourg, have, under Dr.

Related Nerve Cells Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...