October 23, 2025 • 8 mins
Researchers have discovered that the brain plays an active role in the axolotl’s remarkable ability to regenerate its tail, utilizing signaling pathways and a neuropeptide called neurotensin. Blocking brain activity hinders tail regrowth, suggesting a coordinated brain-to-body communication essential for regeneration, potentially offering new avenues for human healing.
Read the full article at https://www.paperleap.com/blog/articles/how-the-axolotl-s-brain-helps-it-regrow-its-tail-0cccu0
Read the full article at https://www.paperleap.com/blog/articles/how-the-axolotl-s-brain-helps-it-regrow-its-tail-0cccu0
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
Welcome to the paper Leap podcast, where a science takes
the mic. Each episode, we discuss cutting edge research, groundbreaking discoveries,
and the incredible people behind them, across disciplines and across
the world. Whether you're a curious mind, a researcher, or
just love learning, you're in the right place before we start.
(00:21):
Don't forget to subscribe so you never miss an insight.
All the content is also available on paper leap dot com.
Speaker 2 (00:29):
Okay, ready, let's start. If you cut off the tail
of an axe lodel, please don't do that, a strange,
almost otherworldly salamander from Mexico, it will grow back, not
just the tail itself, but the muscles, the nerves, and
even the spinal cord inside. This feat would be unthinkable
(00:51):
for humans, whose spinal cord injuries often result in permanent paralysis.
For years, sciencests have been studying the axe Lootto's regeneritive superpowers,
hoping to unlock secrets that kuld someday inspire new treatments
for people. Now, a team of researchers has made a
surprising discovery. It's not just the cells at the injury
(01:15):
site that matter. The Axeltto's brain actually plays an active
role in helping the tail grow. The study, published in
NPJ Regenerative Medicine, comes from scientists at the Marine Biological
Laboratories Eugene Bell Center for Regenerative Biology in Woodshole, Massachusetts,
(01:37):
and the National Human Genome Researched Institute at the National
Institutes of Health in Bethesda, Maryland. Doctor Karen Ecaveri, S. E. Walker,
Ku and S. Burgess found that certain neurons in the
axe lotto's brain switch on after a tail injury, and
without this brain activity, the tale simply doesn't really generate properly.
(02:02):
The axe loodle, also known as Ambistoma mexicanum, is sometimes
called the Mexican walking fish, though it's not a fish
at all. It's a salamander that stays in its larval
stage for life, keeping its feathery gills and wide perpetual
grin Beyond its quirky looks. The axe lottle is a
(02:23):
legend in biology labs because it can regrow almost any
part of its body limbs, tail, heart tissue, parts of
the brain, and even the spinal cord. By contrast, mammals,
including us, don't fare so well if the spinal cord
is injured, nerve cells around the damage tend to die
(02:44):
scar tissue forms, blocking any chance of reconnection. The axe loottle, however,
avoids scar tissue and instead manages to rewire its nerves,
restoring lost functions. For decades, scientists have assumed that regeneration
was mostly a local process, with cells at the wound
(03:06):
site doing all the work, but hints from past studies
suggested something bigger that the brain and other organs far
from the injury might also be involved.
Speaker 1 (03:16):
This new research takes that idea and runs with it.
Speaker 2 (03:20):
Here's what the researchers found. When an axilata loses its tail,
neurons in a specific part of its brain, the medial pallium,
or region roughly equivalent to the hippocampus in mammals, suddenly
light up. This lighting up isn't visible to the naked eye,
but it can be detected through molecular markers of neuronal activity.
Speaker 1 (03:43):
The scientists focused on a signaling pathway involving a protein
called IRK.
Speaker 2 (03:49):
Within just thirty minutes of tail amputation, IRK activity in
these brain cells shot up, and interestingly, this heightened brain
activity lasted more than forty days after the injury.
Speaker 1 (04:02):
In younger axiltels, the response was nearly immediate.
Speaker 2 (04:06):
In adults, it took a little longer, but the same
pattern emerged. The brain joined the regeneration process. To see
if this brain activation was actually necessary, the team did
a clever experiment. They injected an IRK blocking drug directly
into the axi lottl's brain before amputating its tail.
Speaker 1 (04:27):
The results were striking.
Speaker 2 (04:29):
Without IRK activity in the brain, the tail regrew poorly,
with fewer nerves reconnecting and a much shorter regenerate.
Speaker 1 (04:39):
In other words, the brain was essential to regrowth. The
story gets even more interesting.
Speaker 2 (04:46):
The activated brain neurons turned out to produce a signaling
molecule called neural tensin. This neural peptide is already known
in mammals for roles in pain regulation, stress responses, and
even appetite, but in axilottles, neural tensin seems to help
kickstart regeneration. When the researchers blocked neural tensin, tail regrowth stalled.
(05:11):
The hypothalamus, a region deep in the brain that controls
hormone release, failed to boast production of growth hormone releasing hormone,
a key player in tissue growth. The usual inflammatory response
that helps clear debris and prepare the wound site for rebuilding.
Speaker 1 (05:29):
Also fizzled out.
Speaker 2 (05:30):
In short neural tensin was a lynchpin. Without it, regeneration faltered.
This research adds a new dimension to our understanding of regeneration.
It shows that in axi lootls, the brain communicates with
distant injury sites, coordinating the rebuilding process. Instead of thinking
(05:51):
of regeneration as a purely local repair job, we might
need to think of it as a whole body response.
This could eventually change how we approach spinal cord injuries
or other types of tissue damage. We know where bodies
don't regenerate like axe lootels, but we do share many
of the same molecular players, like irk signaling pathways and neuropeptides.
Speaker 1 (06:14):
If we can figure out how.
Speaker 2 (06:15):
To harness or mimic these brain to body signals, we
might be able to improve healing or even spark regeneration
where it normally doesn't happen.
Speaker 1 (06:26):
It's still early days, of course.
Speaker 2 (06:28):
What works in a salamander won't simply copy paste into people,
but the principle is clear.
Speaker 1 (06:34):
The brain is also part of the body's repair toolkit.
Speaker 2 (06:38):
This study also fits into a growing body of evidence
showing that long distance communication is a hallmark of regeneration
in cockroaches. Severing the connection between the brain and an injured.
Speaker 1 (06:51):
Limb prevents proper regrowth.
Speaker 2 (06:54):
In frogs and fish, hormones released far from the wound
site influence whether new tissue. What makes the axe laddle
special is its ability to orchestrate all these signals seamlessly
without scarring. That's something scientists and doctors dream of replicating.
(07:14):
Follow Up discoveries in this direction could lead to a
future where a spinal cord injury wouldn't mean paralysis, or
where a damaged heart tissue after a heart attack could
be coaxed to regrow. It might sound like science fiction,
but studies like this one keep pushing the boundaries of
what we know whatever will help us leap in that direction.
(07:36):
One thing is clear, the axe laddle has much more
to teach us.
Speaker 1 (07:44):
That's it for this episode of the paper Leaf Podcast.
If you found it thought provoking, fascinating, or just informative,
share it with the fellow science nerd. For more research
highlights and full articles, visit paperleaf dot com. Also make
sure to subscribe to the podcast. We've got plenty more
discoveries to unpack until next time. Keep questioning, keep learning,
Welcome to the paper Leap podcast, where a science takes
the mic. Each episode, we discuss cutting edge research, groundbreaking discoveries,
and the incredible people behind them, across disciplines and across
the world. Whether you're a curious mind, a researcher, or
just love learning, you're in the right place before we start.
(00:21):
Don't forget to subscribe so you never miss an insight.
All the content is also available on paper leap dot com.
Speaker 2 (00:29):
Okay, ready, let's start. If you cut off the tail
of an axe lodel, please don't do that, a strange,
almost otherworldly salamander from Mexico, it will grow back, not
just the tail itself, but the muscles, the nerves, and
even the spinal cord inside. This feat would be unthinkable
(00:51):
for humans, whose spinal cord injuries often result in permanent paralysis.
For years, sciencests have been studying the axe Lootto's regeneritive superpowers,
hoping to unlock secrets that kuld someday inspire new treatments
for people. Now, a team of researchers has made a
surprising discovery. It's not just the cells at the injury
(01:15):
site that matter. The Axeltto's brain actually plays an active
role in helping the tail grow. The study, published in
NPJ Regenerative Medicine, comes from scientists at the Marine Biological
Laboratories Eugene Bell Center for Regenerative Biology in Woodshole, Massachusetts,
(01:37):
and the National Human Genome Researched Institute at the National
Institutes of Health in Bethesda, Maryland. Doctor Karen Ecaveri, S. E. Walker,
Ku and S. Burgess found that certain neurons in the
axe lotto's brain switch on after a tail injury, and
without this brain activity, the tale simply doesn't really generate properly.
(02:02):
The axe loodle, also known as Ambistoma mexicanum, is sometimes
called the Mexican walking fish, though it's not a fish
at all. It's a salamander that stays in its larval
stage for life, keeping its feathery gills and wide perpetual
grin Beyond its quirky looks. The axe lottle is a
(02:23):
legend in biology labs because it can regrow almost any
part of its body limbs, tail, heart tissue, parts of
the brain, and even the spinal cord. By contrast, mammals,
including us, don't fare so well if the spinal cord
is injured, nerve cells around the damage tend to die
(02:44):
scar tissue forms, blocking any chance of reconnection. The axe loottle, however,
avoids scar tissue and instead manages to rewire its nerves,
restoring lost functions. For decades, scientists have assumed that regeneration
was mostly a local process, with cells at the wound
(03:06):
site doing all the work, but hints from past studies
suggested something bigger that the brain and other organs far
from the injury might also be involved.
Speaker 1 (03:16):
This new research takes that idea and runs with it.
Speaker 2 (03:20):
Here's what the researchers found. When an axilata loses its tail,
neurons in a specific part of its brain, the medial pallium,
or region roughly equivalent to the hippocampus in mammals, suddenly
light up. This lighting up isn't visible to the naked eye,
but it can be detected through molecular markers of neuronal activity.
Speaker 1 (03:43):
The scientists focused on a signaling pathway involving a protein
called IRK.
Speaker 2 (03:49):
Within just thirty minutes of tail amputation, IRK activity in
these brain cells shot up, and interestingly, this heightened brain
activity lasted more than forty days after the injury.
Speaker 1 (04:02):
In younger axiltels, the response was nearly immediate.
Speaker 2 (04:06):
In adults, it took a little longer, but the same
pattern emerged. The brain joined the regeneration process. To see
if this brain activation was actually necessary, the team did
a clever experiment. They injected an IRK blocking drug directly
into the axi lottl's brain before amputating its tail.
Speaker 1 (04:27):
The results were striking.
Speaker 2 (04:29):
Without IRK activity in the brain, the tail regrew poorly,
with fewer nerves reconnecting and a much shorter regenerate.
Speaker 1 (04:39):
In other words, the brain was essential to regrowth. The
story gets even more interesting.
Speaker 2 (04:46):
The activated brain neurons turned out to produce a signaling
molecule called neural tensin. This neural peptide is already known
in mammals for roles in pain regulation, stress responses, and
even appetite, but in axilottles, neural tensin seems to help
kickstart regeneration. When the researchers blocked neural tensin, tail regrowth stalled.
(05:11):
The hypothalamus, a region deep in the brain that controls
hormone release, failed to boast production of growth hormone releasing hormone,
a key player in tissue growth. The usual inflammatory response
that helps clear debris and prepare the wound site for rebuilding.
Speaker 1 (05:29):
Also fizzled out.
Speaker 2 (05:30):
In short neural tensin was a lynchpin. Without it, regeneration faltered.
This research adds a new dimension to our understanding of regeneration.
It shows that in axi lootls, the brain communicates with
distant injury sites, coordinating the rebuilding process. Instead of thinking
(05:51):
of regeneration as a purely local repair job, we might
need to think of it as a whole body response.
This could eventually change how we approach spinal cord injuries
or other types of tissue damage. We know where bodies
don't regenerate like axe lootels, but we do share many
of the same molecular players, like irk signaling pathways and neuropeptides.
Speaker 1 (06:14):
If we can figure out how.
Speaker 2 (06:15):
To harness or mimic these brain to body signals, we
might be able to improve healing or even spark regeneration
where it normally doesn't happen.
Speaker 1 (06:26):
It's still early days, of course.
Speaker 2 (06:28):
What works in a salamander won't simply copy paste into people,
but the principle is clear.
Speaker 1 (06:34):
The brain is also part of the body's repair toolkit.
Speaker 2 (06:38):
This study also fits into a growing body of evidence
showing that long distance communication is a hallmark of regeneration
in cockroaches. Severing the connection between the brain and an injured.
Speaker 1 (06:51):
Limb prevents proper regrowth.
Speaker 2 (06:54):
In frogs and fish, hormones released far from the wound
site influence whether new tissue. What makes the axe laddle
special is its ability to orchestrate all these signals seamlessly
without scarring. That's something scientists and doctors dream of replicating.
(07:14):
Follow Up discoveries in this direction could lead to a
future where a spinal cord injury wouldn't mean paralysis, or
where a damaged heart tissue after a heart attack could
be coaxed to regrow. It might sound like science fiction,
but studies like this one keep pushing the boundaries of
what we know whatever will help us leap in that direction.
(07:36):
One thing is clear, the axe laddle has much more
to teach us.
Speaker 1 (07:44):
That's it for this episode of the paper Leaf Podcast.
If you found it thought provoking, fascinating, or just informative,
share it with the fellow science nerd. For more research
highlights and full articles, visit paperleaf dot com. Also make
sure to subscribe to the podcast. We've got plenty more
discoveries to unpack until next time. Keep questioning, keep learning,
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