Nav: Home

Needing a change? Researchers find GABA is the key to metamorphosis

March 31, 2020

Tsukuba, Japan - Metamorphosis, or a dramatic change in physical appearance, is a normal part of the life cycle of many animals, carried out to take advantage of different ecological niches. Yet the process of metamorphosis--how a caterpillar becomes a butterfly, or a tadpole transforms into a frog--is not well understood and has only been studied in a small number of species.

In a study published this week in Current Biology, a team led by researchers from the University of Tsukuba investigated the role of various neurotransmitters in the regulation of metamorphosis, identifying GABA as a key regulator in the model sea squirt Ciona intestinalis.

Ciona are some of the closest living relatives of vertebrates. Starting life as tadpole-like larvae, Ciona undergo a metamorphosis into vase-shaped adults that is triggered by their attachment to a solid surface.

"Ciona have organs called adhesive papillae that sense when the animal attaches to a surface, triggering metamorphosis," explains Professor Yasunori Sasakura, senior author. "The adhesive papillae contain sensory neurons that transmit signals to the rest of the body, suggesting that the nervous system plays an essential role in initiating metamorphosis."

To investigate the role of the nervous system in metamorphosis, the researchers treated Ciona larvae with various neurotransmitters, among which only GABA induced the physical changes associated with maturation. Upon blocking the genes required for GABA synthesis, transport, and maturation, the researchers observed decreased induction of metamorphosis, confirming they had found the right regulatory molecule.

GABA, or gamma aminobutyric acid, is one of the main neurotransmitters in mammals. It is usually thought of as an inhibitory molecule because it blocks certain signals in the brain, decreasing nervous system activity. Interestingly, however, the researchers found that this was not the case in Ciona metamorphosis.

"Using expression analysis and gene knockout/knockdown assays, we showed that GABA activates the neurons expressing gonadotropin-releasing hormone (GnRH), which is essential for reproductive maturation in vertebrates," says Professor Sasakura. "Knocking out the genes encoding GnRH showed that it is essential for metamorphosis in Ciona larvae and confirmed its place as the downstream component of GABA-mediated regulation."

Further experimentation showed that while larvae lacking GnRH could not carry out the initial steps of metamorphosis, they did exhibit normal adult organ growth. In contrast, no adult organ growth was observed in GABA mutants, suggesting that GABA is essential for all metamorphic events.

The researchers now hope to understand how the GABA-GnRH pathway causes the dramatic physical changes that occur during Ciona metamorphosis and, given the wide conservation of these molecules among animals, to explore whether the GABA-GnRH mechanism plays a role in the metamorphosis of other animal species.
-end-


University of Tsukuba

Related Neurons Articles:

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.
Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.
How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.
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.
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

Our Relationship With Water
We need water to live. But with rising seas and so many lacking clean water – water is in crisis and so are we. This hour, TED speakers explore ideas around restoring our relationship with water. Guests on the show include legal scholar Kelsey Leonard, artist LaToya Ruby Frazier, and community organizer Colette Pichon Battle.
Now Playing: Science for the People

#569 Facing Fear
What do you fear? I mean really fear? Well, ok, maybe right now that's tough. We're living in a new age and definition of fear. But what do we do about it? Eva Holland has faced her fears, including trauma and phobia. She lived to tell the tale and write a book: "Nerve: Adventures in the Science of Fear".
Now Playing: Radiolab

Uncounted
First things first: our very own Latif Nasser has an exciting new show on Netflix. He talks to Jad about the hidden forces of the world that connect us all. Then, with an eye on the upcoming election, we take a look back: at two pieces from More Perfect Season 3 about Constitutional amendments that determine who gets to vote. Former Radiolab producer Julia Longoria takes us to Washington, D.C. The capital is at the heart of our democracy, but it's not a state, and it wasn't until the 23rd Amendment that its people got the right to vote for president. But that still left DC without full representation in Congress; D.C. sends a "non-voting delegate" to the House. Julia profiles that delegate, Congresswoman Eleanor Holmes Norton, and her unique approach to fighting for power in a virtually powerless role. Second, Radiolab producer Sarah Qari looks at a current fight to lower the US voting age to 16 that harkens back to the fight for the 26th Amendment in the 1960s. Eighteen-year-olds at the time argued that if they were old enough to be drafted to fight in the War, they were old enough to have a voice in our democracy. But what about today, when even younger Americans are finding themselves at the center of national political debates? Does it mean we should lower the voting age even further? This episode was reported and produced by Julia Longoria and Sarah Qari. Check out Latif Nasser's new Netflix show Connected here. Support Radiolab today at Radiolab.org/donate.