Stinging tree may reveal new ways to treat chronic pain

A New Zealand stinging tree produces toxins that could hold clues for future pain medication, according to researchers at The University of Queensland (UQ).

In a quest to find new molecules that affect pain pathways, Dr. Thomas Durek, Dr. Sam Robinson and a team from UQ’s Institute for Molecular Bioscience (IMB) studied toxins from tree nettle – one of New Zealand’s most poisonous plants. This nettle species causes painful stings that can be fatal.

The tree nettle toxins were found to activate pain receptors in a new way. “The New Zealand tree nettle can grow up to four meters tall and its leaves and stems are covered with stinging hairs that pierce the skin and deliver venom which causes long-lasting pain,” said Dr. Robinson.

Fossil remains show that a large flightless bird known as the Moa would frequently eat the tree nettle. It’s likely that the strong toxins evolved to fend off the now-extinct bird.

“COVID made it difficult to source nettles, but to keep our research going through the pandemic, we managed to source seeds from the New Zealand tree nettle and grow the plant under quarantine in the lab,” said Dr. Robinson.

Professor Irina Vetter, Director of IMB’s Centre for Pain Research, said understanding pain pathways was key to finding new ways to treat chronic pain.

“Animal venoms have been studied for decades but plants have evolved toxins differently, and this gives us a chance to find molecules that work in a unique way,” explained Professor Vetter.

Around the world, there are hundreds of tree nettles with stinging hairs. The researchers intend to study as many as possible to find new treatments for common pain. The goal is to tackle pain more effectively without side effects and addiction.

With travel bans lifting, Dr. Gilding plans to go to Vietnam later this year to experience anything that stings. “There are several hundred nettles in the Urticaceae family with stinging hairs around the world – we’re keen to compare how they have evolved and whether they all use the same toxins.”

The research is published in the Journal of Biological Chemistry.

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By Katherine Bucko, Earth.com Staff Writer