Australian prickly trees inject people with spider-like venom: study


The biting trees of Australia have leaves that look “a bit fuzzy and not so scary” when you first see them, explains Pain researcher Irina Vetter. But don’t be fooled.“If you take a closer look you can see that the blur is actually just tiny little needles of silica filled with liquid, which we can really think of as venom now,” Vetter said. As it happens host Carol Off.

“And it’s injected into your skin like a hypodermic needle. ”

Vetter, a pain researcher at the University of Queensland, has co-authored a new study examining the molecular structure of the poison produced by the Australian tree Dendrocnid excelsa.

Researchers have found that the leaves produce a previously unidentified type of neurotoxin that targets pain receptors much like the venom of a poisonous spider or scorpion.

The results, published in the journal Science Advances, could have implications for how we treat chronic pain.

“It’s a little unpleasant, to say the least”

Dendrocnid excelsa is a member of a family of stinging trees in Australia, known locally as gympie-gympie trees.

Much like the common nettle found in North America and Europe, the leaves of the gympie-gympie release a substance that causes a strong burning and stinging sensation on the skin – but it’s much worse.

“As the hours go by, as it progresses, you feel a sort of strange hum, crawl, and pains. And it can actually be triggered for days and weeks after just by showering, for example, or scratching the stung area, ”Vetter said.

“It’s a bit unpleasant, to say the least. “

From a distance it looks like fuzz. But take a closer look and you will see that the gympie-gympie leaves are covered with needles filled with fluid. (Submitted by Irina Vetter)

She would know.

“I met them walking in the bush. But sometimes I looked for a shot on purpose to investigate a little more what is going on, ”she said.

“It really started with a little curiosity as to why the pain is so bad. “

A defensive mechanism

Vetter says the trees likely developed the neurotoxins for the same reason an insect or animal would secrete poisonous venom – as a form of self-defense on the part of creatures that would swallow them up.

“This is a remarkable case of what we call a convergent evolution. Nature therefore has a problem. How do you deter a herbivore or a predator? And nature has found basically the same solution – these toxins that act on the nerves sensitive to pain ”. she says.

A close-up of the leaves of Dendrocnidus excelsa shows the tiny needles that inject a venom-like neurotoxin that causes severe and lasting pain. (Submitted by Irina Vetter)

But there are critters that nibble on the gympie-gympie leaves without problem, including various insects, and small marsupials called the pademelon.

“So we don’t know if the pademelon, for example, is just a very hard cookie or if something else is going on,” Vetter said.

But the main goal of her research, she says, is to better understand how pain works, so that we can treat it better.

“Because the pain lasts so long, we hope it might give us some information to understand how chronic pain develops,” said Vetter.

The researchers have already created a synthetic compound of the neurotoxins – which they named gympietides – for further study.

“The hope is that once you find something that works on a pain-sensitive nerve to turn it on, it’s actually not that hard to change the chemical structure of it, to change it. transform into something that would block a pain signal, ”Vetter told me.

“Maybe we can do something useful with it. “

Written by Sheena Goodyear. Interview conducted by Lisa Bryn Rundle.


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