Nav: Home

Calcium channels team up to activate excitable cells

May 18, 2016

Voltage-gated calcium channels open in unison, rather than independently, to allow calcium ions into and activate excitable cells such as neurons and muscle cells, researchers with UC Davis Health System and the University of Washington have found.

The research defies earlier electrophysiology canon and undermines the previously held belief that calcium channels function independently. The study is published online in the journal eLife.

The finding is important, the researchers said, because understanding how these channels collaborate could lead to improved therapies that target aberrant calcium channels in malfunctioning cells. Dysfunctional calcium channels can be found in a variety of conditions, such as epilepsy and Parkinson's disease.

"In cardiac muscle, if these channels don't coordinate their firing, it will have detrimental repercussions on the reliability of the cardiac muscle contractions," said Luis Fernando Santana, professor and chair of the Department of Physiology and Membrane Biology at UC Davis. "In neurons, if they don't gang up, they don't get the potentiation they need to sustain repetitive firing.

"In a previous study we found that a bad channel paired with a good channel can turn both of them bad," Santana said. "So, you don't need a lot of bad channels to make a cell dysfunctional and show pathological behavior."

To study these tiny channels, the researchers used high-resolution microscopy, electrophysiological measurements and optogenetic technologies -- light-sensitive probes that can stimulate neurons to fire electrical signals -- to study rat hippocampal neurons. They found that when cells begin responding to calcium, channels start grouping in clusters of two or more and open cooperatively, allowing cells to fire more rapidly.

"This is a clear demonstration that voltage-gated calcium channels can couple to amplify the influx of calcium and control a cell's excitability," Santana added. "This coordination has a powerful influence on the behavior of neurons and other excitable cells."

The channels coordinate through a protein called calmodulin, which binds to calcium and helps carry it through the channel.

"Normally these channels don't touch each other," Santana said. "However, a little bit of calcium comes through and calmodulin serves as a bridge between neighboring channels. Influenced by the channel that opens first, they begin opening in unison, bringing channels together."

The researchers also found that these clusters dissolve much more slowly than the associated calcium. This "molecular memory" may allow cells to anticipate future firings, increasing their efficiency.

"It's always been a contradiction," noted Santana. "In a heart muscle, five to 10 channels have to open to activate calcium release reliably during the activation of contraction, but the chance of such a cluster of channels firing simultaneously is minuscule unless there is some cooperation."
-end-
Other authors are Claudia Moreno and Sendoa Tajada of UC Davis; and Rose Dixon, Can Yuan, Ximena Opitz-Araya and Marc Binder of the University of Washington.

This research was funded by the National Heart, Lung, and Blood Institute (HL085870 and HL085686); National Institute of Neurological Disorders and Stroke (NS077863); and American Heart Association (15SDG25560035).

UC Davis Health System is improving lives and transforming health care by providing excellent patient care, conducting groundbreaking research, fostering innovative, interprofessional education, and creating dynamic, productive partnerships with the community. For more information, visit healthsystem.ucdavis.edu.

University of California - Davis Health System

Related Neurons Articles:

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.
Shaping the social networks of neurons
Identification of a protein complex that attracts or repels nerve cells during development.
With these neurons, extinguishing fear is its own reward
The same neurons responsible for encoding reward also form new memories to suppress fearful ones, according to new research by scientists at The Picower Institute for Learning and Memory at MIT.
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.
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.
More Neurons News and Neurons 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.