Nav: Home

A docking site per calcium channel cluster

June 13, 2017

A study co-led by Ryuichi Shigemoto, Professor at the Institute of Science and Technology Austria (IST Austria), with Alain Marty, Professor at Université Paris Descartes, uncovers that a single docking site may use a single cluster of calcium channels and that both the number of docking sites and the number of calcium clusters change in parallel with brain age. This establishes the first clear link between the morphology and function of docking sites. The study was published today in PNAS.

At a chemical synapse, signal transmission requires an elaborate sequence of events. It starts when an electrical signal, the action potential, reaches the synaptic terminal of the presynaptic neuron. This causes voltage-gated calcium channel to open. Calcium ions rapidly stream into the presynaptic terminal and the calcium concentration in the presynaptic terminal rises. This allows synaptic vesicles filled with neurotransmitter to fuse with the plasma membrane and release the neurotransmitters into the synaptic cleft. Speed is essential in information transmission. Therefore, before the action potential even arrives at the presynaptic terminal, vesicles containing neurotransmitter line up in a fusion-ready state at docking sites in the presynaptic terminal. When the action potential reaches the presynaptic terminal, the vesicles can rapidly fuse and release the neurotransmitter. Functionally, docking sites limit the maximum number of vesicles that can be released at each action potential, this determines the strength of the synapse. Until now, a clear link between the functional aspect of docking sites and their morphological aspect as sites where vesicles dock could not be established in the mammalian brain.

Shigemoto and colleagues used a high-resolution electron microscopy technique to look closely at the presynaptic terminal of a particular synapse in the mouse. They found that the number of functional docking sites matches the number of clusters of voltage-gated calcium channels in the presynaptic terminal. In addition, the number of docking sites and the number of calcium clusters change in parallel with brain age and synaptic size. This led the researchers to a major conclusion, as Shigemoto explains: "Based on our results, we suggest that for each docking site, there is a corresponding cluster of voltage-gated calcium channels. We propose a model in which each cluster of calcium channels is surrounded by enough free space to allow one synaptic vesicle to fuse in any direction."

Ryuichi Shigemoto joined IST Austria as Professor in 2013. He and his group investigate the functional roles of ion channels and neurotransmitter receptors in neurons and glia using morphological, electrophysiological and molecular biological techniques. Shigemoto received an ERC Advanced Grant in 2016. Walter Kaufmann, Staff Scientist in IST Austria's Electron Microscopy Facility, performed part of the research for the current study.
-end-


Institute of Science and Technology Austria

Related Neurotransmitter Articles:

How procrastinators and doers differ genetically
Some people tend to postpone actions. In women, this trait is associated with a genetic predisposition towards a higher level of dopamine in the brain.
Serotonin boosts neuronal powerplants protecting against stress
Research from the Vaidya and Kolthur-Seetharam groups (TIFR) shows that the neurotransmitter serotonin enhances the production and functions of neuronal mitochondria, the powerhouse of the cell, and protect against stress.
Fitting a right hand in a left-handed mitten
Many biomolecules come in two versions that are each other's mirror image, like a left and a right hand.
Hopkins researchers ID neurotransmitter that helps cancers progress
Using human cancer cells, tumor and blood samples from cancer patients, researchers at Johns Hopkins Medicine have uncovered the role of a neurotransmitter in the spread of aggressive cancers.
Dopamine regulates sex differences in worms
Dopamine is responsible for sex-specific variations in common behaviors, finds a study of worm movements published in JNeurosci.
Feinstein CEO, global researchers show significance of neurotransmitter in viral infection
Feinstein Institute for Medical Research President and CEO Kevin J.
Tak Mak lab discovers how the immune system 'thinks'
New research from the laboratory of cancer scientist Dr. Tak Mak, renowned for cloning the human T-cell receptor, has demonstrated that immune cells make brain chemicals to fight off infections.
How the brain reacts to loss of vision
If mice lose their vision immediately after birth due to a genetic defect, this has a considerable impact, both on the organisation of the cerebral cortex and on memory ability.
New knowledge on how neurons talk to muscles
Researchers at Karolinska Institutet in Sweden have discovered a new way in which nerve cells can control movement.
Link found between neurotransmitter imbalance, brain connectivity in those with autism
Researchers from the University of Missouri School of Medicine and MU Thompson Center for Autism and Neurodevelopmental Disorders identified a link between a neurotransmitter imbalance and brain connectivity between regions of the brain that play a role in social communication and language.
More Neurotransmitter News and Neurotransmitter Current Events

Top Science Podcasts

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

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.