African mole-rats immune to 'wasabi pain'

May 30, 2019

A new report in Science provides the first evidence of a mammal -- the highveld mole-rat -- being immune to pain from exposure to allyl isothiocyanate, or AITC, the active ingredient of wasabi.

The scientists who studied the animals say that understanding how these African rodents evolved to be insensitive to this specific type of pain could point to new directions for solving pain in humans.

"Mole-rats are extremely curious animals and we have been studying them at UIC for more than 20 years," said study co-author Thomas Park, professor of biological sciences at the University of Illinois at Chicago College of Liberal Arts and Sciences. "This new discovery -- that they have evolved to be insensitive to certain pain stimuli common in their environment -- is another example of the cool biological lessons to be learned from studying them."

Park worked alongside scientists from the Max Delbruck Center for Molecular Medicine in Berlin and the University of Pretoria in Pretoria, South Africa, on the study. The research was conducted at UIC and in South Africa.

They exposed the paws of eight species of mole-rats to three compounds that induce a pain-like response -- AITC, an acidic solution with a pH similar to lemon juice and capsaicin, the spicy ingredient in chili peppers. The scientists monitored behaviors, such as the time an animal spent licking its paws after being exposed to a small drop of the chemicals. They compared these observed behaviors with those they observed in mice when exposed to the same compounds. Following euthanasia, the scientists also extracted spinal cord tissue and nerve tissues for analysis.

Three of the species were immune to the acidic solution and two were immune to capsaicin, but the naked mole-rat was the only species immune to both.

They also found that the highveld mole-rate was immune to exposure to the AITC compound.

"This is an awesome finding because the highveld mole-rat is the only mammal known to be immune to 'wasabi pain,'" Park said. "It turns out that highveld mole-rats share their tunnels, their natural environment in Africa, with a stinging ant species, the natal droptail ant. The ant's sting normally activates the same pain receptors that respond to wasabi. Over time, the highveld mole-rats evolved to become unaffected by the sting."

Park and his colleagues also analyzed genetic materials from the samples they took from the mole-rats and found that the nerves of highveld mole-rats had an unusually large number of tiny structures called leak channels on their surface.

"Nature and evolution solved a pain problem for the highveld mole-rat. The leak channels make the nerves unable to convey messages about wasabi pain to the brain," Park said. "Instead of delivering the signal from the receptor to the brain, the leak channels divert the signal."

The researchers say that this finding is particularly interesting, as the evolutionary change for this species of mole-rate occurred over a short period of time -- 7 million years. The naked mole-rats also developed their immunity to the acidic solution and capsaicin quickly.

"That may seem like a long time, but in evolutionary biology, 7 million years is considered to be quite rapid," Park said.

"When we find out how to add leak channels to our own pain cells, we'll have a new way of fighting pain, without the side effect of addiction from external pain killers," he said.
-end-
This research was funded by grants from the National Science Foundation, the European Research Council and the Deutsche Forschungsgemeinschaft SFB 958.

University of Illinois at Chicago

Related Pain Articles from Brightsurf:

Pain researchers get a common language to describe pain
Pain researchers around the world have agreed to classify pain in the mouth, jaw and face according to the same system.

It's not just a pain in the head -- facial pain can be a symptom of headaches too
A new study finds that up to 10% of people with headaches also have facial pain.

New opioid speeds up recovery without increasing pain sensitivity or risk of chronic pain
A new type of non-addictive opioid developed by researchers at Tulane University and the Southeast Louisiana Veterans Health Care System accelerates recovery time from pain compared to morphine without increasing pain sensitivity, according to a new study published in the Journal of Neuroinflammation.

The insular cortex processes pain and drives learning from pain
Neuroscientists at EPFL have discovered an area of the brain, the insular cortex, that processes painful experiences and thereby drives learning from aversive events.

Pain, pain go away: new tools improve students' experience of school-based vaccines
Researchers at the University of Toronto and The Hospital for Sick Children (SickKids) have teamed up with educators, public health practitioners and grade seven students in Ontario to develop and implement a new approach to delivering school-based vaccines that improves student experience.

Pain sensitization increases risk of persistent knee pain
Becoming more sensitive to pain, or pain sensitization, is an important risk factor for developing persistent knee pain in osteoarthritis (OA), according to a new study by researchers from the Université de Montréal (UdeM) School of Rehabilitation and Hôpital Maisonneuve Rosemont Research Centre (CRHMR) in collaboration with researchers at Boston University School of Medicine (BUSM).

Becoming more sensitive to pain increases the risk of knee pain not going away
A new study by researchers in Montreal and Boston looks at the role that pain plays in osteoarthritis, a disease that affects over 300 million adults worldwide.

Pain disruption therapy treats source of chronic back pain
People with treatment-resistant back pain may get significant and lasting relief with dorsal root ganglion (DRG) stimulation therapy, an innovative treatment that short-circuits pain, suggests a study presented at the ANESTHESIOLOGY® 2018 annual meeting.

Sugar pills relieve pain for chronic pain patients
Someday doctors may prescribe sugar pills for certain chronic pain patients based on their brain anatomy and psychology.

Peripheral nerve block provides some with long-lasting pain relief for severe facial pain
A new study has shown that use of peripheral nerve blocks in the treatment of Trigeminal Neuralgia (TGN) may produce long-term pain relief.

Read More: Pain News and Pain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.