Neurotoxin in cigarette smoke worsens pain in spinal cord injuries

June 15, 2017 by Emil Venere
People with spinal cord injuries may suffer “neuropathic pain” in various parts of the body. Credit: Purdue University photo/Michel Schweinsberg

Researchers have identified a key component in cigarette smoke that worsens pain in people with spinal cord injury, suggesting that a critical element within tobacco is responsible for such pain-inducing effects.

"Findings support anecdotal information suggesting that smoking increases in patients with injuries," said Riyi Shi (pronounced Ree Shee), a professor of neuroscience and in Purdue University's Department of Basic Medical Sciences, College of Veterinary Medicine and Weldon School of Biomedical Engineering. "This could be felt in the leg and upper extremities, or in any part of the body."

A toxin from has been shown to cause pain in animals with spinal cord injuries. The same toxin is known to activate pain sensors in .

The research showed that a neurotoxin called contained in cigarette smoke intensified neuropathic pain after spinal cord injuries in rats. Acrolein is known to worsen pain by activating and causing a proliferation of called TRPA1, or transient receptor potential ankyrin-1, found in nerve fibers.

The findings are detailed in a research paper appearing on Aug. 15 in the Journal of Neurological Sciences. The paper, published online May 22, was co-authored by Shi and graduate students Breanne Butler and Glen Acosta.

"Previously, it was reported that people with spinal cord injury-induced chronic neuropathic pain have experienced heightened when smoking tobacco cigarettes, and less pain following the termination of smoking," Shi said. "However, the molecular mechanisms of smoke-induced hypersensitivity are not yet clear. We show in the current study not only that the inhalation of cigarette smoke can worsen the pain, but inhaling acrolein alone, apart from cigarette smoke, at a concentration similar to that emitted from cigarettes, can produce significant increases in pain-related behavior after spinal cord injury as well. Furthermore, the intensified pain behavior due to acrolein inhalation was reduced when an acrolein scavenger, phenelzine, was administered to the animals during acrolein exposure."

The study could open the door to a variety of possible preventive or therapeutic approaches to mitigate pain affecting the quality of life in spinal cord injury victims.

One of the principal impacts of the discovery is the possibility of reducing pain by using acrolein-scavenging drugs such as phenelzine, an anti-depressant approved by the U.S. Food and Drug Administration. Other potential FDA-approved anti-acrolein drugs including hydralazine, a medication for hypertension, and dimercarprol, an acute heavy metal poisoning treatment, have been tested and shown to be effective acrolein scavengers in Shi's lab. The drugs are thought to mitigate pain in active smokers, but also among those with pain caused by second-hand smoke for people with .

Acrolein also is produced by the body in response to spinal cord injury, and this natural source of the neurotoxin has been found to increase pain. However, the new research findings are the first showing that both acrolein introduced from an external source and cigarette smoke itself increases pain. A potential mechanism is that acrolein may increase pain by activating the TRPA1 receptors after spinal cord injury, as shown in some of Shi's previous work.

"The pain caused by cigarettes is noticeably more severe than acrolein alone, so there could be other compounds in cigarette smoke that also play a role," he said.

Explore further: New pain mechanisms revealed for neurotoxin in spinal cord injury

More information: Breanne Butler et al. Exogenous Acrolein intensifies sensory hypersensitivity after spinal cord injury in rat, Journal of the Neurological Sciences (2017). DOI: 10.1016/j.jns.2017.05.039

Related Stories

New pain mechanisms revealed for neurotoxin in spinal cord injury

November 24, 2015
A toxin released by the body in response to spinal cord injuries increases pain by causing a proliferation of channels containing pain sensors, new research shows, and this hypersensitivity also extends to peripheral nerves ...

Toxin from tobacco smoke could increase pain in spinal cord injury

December 3, 2014
A neurotoxin called acrolein found in tobacco smoke that is thought to increase pain in people with spinal cord injury has now been shown to accumulate in mice exposed to the equivalent of 12 cigarettes daily over a short ...

Drug may reduce chronic pain for spinal cord injuries

October 31, 2013
(Medical Xpress)—Researchers have discovered that a known neurotoxin may cause chronic pain in people who suffer from paralysis, and a drug that has been shown to remove the toxin might be used to treat the pain.

An old drug with new potential: WWII chemical-weapon antidote shows early promise as treatment for spinal cord injuries

March 29, 2017
A drug developed during World War II as an antidote for a chemical warfare agent has been found to be effective at suppressing a neurotoxin that worsens the pain and severity of spinal cord injuries, suggesting a new tool ...

Startup commercializing innovation to reduce neurotoxin that damages nerve cells, triggers pain

September 16, 2014
A Purdue startup is commercializing a technology that could reduce the symptoms and pain of neurological disease and injury, including multiple sclerosis, neuropathic pain and Parkinson's disease.

Recommended for you

Investigating patterns of degeneration in Alzheimer's disease

November 17, 2017
Alzheimer's disease (AD) is known to cause memory loss and cognitive decline, but other functions of the brain can remain intact. The reasons cells in some brain regions degenerate while others are protected is largely unknown. ...

Brain activity buffers against worsening anxiety

November 17, 2017
Boosting activity in brain areas related to thinking and problem-solving may also buffer against worsening anxiety, suggests a new study by Duke University researchers.

Study may point to new treatment approach for ASD

November 17, 2017
Using sophisticated genome mining and gene manipulation techniques, researchers at Vanderbilt University Medical Center (VUMC) have solved a mystery that could lead to a new treatment approach for autism spectrum disorder ...

Neuroscience research provides evidence the brain is strobing, not constant

November 17, 2017
It's not just our eyes that play tricks on us, but our ears. That's the finding of a landmark Australian-Italian collaboration that provides new evidence that oscillations, or 'strobes', are a general feature of human perception.

Neuroscientists find chronic stress skews decisions toward higher-risk options

November 16, 2017
Making decisions is not always easy, especially when choosing between two options that have both positive and negative elements, such as deciding between a job with a high salary but long hours, and a lower-paying job that ...

Paraplegic rats walk and regain feeling after stem cell treatment

November 16, 2017
Engineered tissue containing human stem cells has allowed paraplegic rats to walk independently and regain sensory perception. The implanted rats also show some degree of healing in their spinal cords. The research, published ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

TheGhostofOtto1923
not rated yet Jun 15, 2017
This may not be enough to get idiot smokers to suffer through the pain of withdrawal, but it may be enough for insurance companies to withhold funding for expensive treatments that wouldnt be necessary if they didnt smoke to begin with.

And maybe THIS will be enough to get them to stop.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.