Cigarette smoke found to increase pain sensitivity

Cigarettes are something that have been proven to negatively affect our health, but smokers are still smoking them due to their addictive nature. Much of this addiction stems from many of the chemicals found in cigarettes, producing a calming and relaxing sensation. However, according to a new study, cigarette smoke can actually worsen pain, especially in people with a spinal cord injury.

Effects of a spinal cord injury

A spinal cord injury is damage to any part of the spinal cord or nerves at the end of the spinal canal. It often leaves those affected with permanent changes in strength, sensation, and other bodily functions below injury level. While advances in medical research have come a long way, unfortunately, most of these patients become wheelchair bound and repairing the spinal cord is extremely complex.

A neurotoxin called acrolein contained in cigarette smoke was found to intensify neuropathic pain after spinal cord injuries in rat models. Acrolein essentially activated pain sensors in nerve fibers.

“Findings support anecdotal information suggesting that smoking increases pain in patients with spinal cord injuries, this neuropathic pain could be felt in the leg and upper extremities, or in any part of the body,” said Riyi Shi, a professor of neuroscience and biomedical engineering in Purdue University’s Department of Basic Medical Sciences.

Substance found in smoke increases pain sensitivity

The researchers found that acrolein worsened pain by activating and causing a proliferation of pain receptors called TRPA1 (transient receptor potential ankyrin-1), which is found in nerve fibers.

They also mentioned that previous studies have shown spinal cord injury victims reported heightened pain sensitivity when smoking tobacco cigarettes and less pain once quitting. This new study has specifically isolated the acrolein compound found in cigarette smoke to cause this pain-related behavior after spinal cord injury.
However, the exact molecular mechanisms of smoke-induced hypersensitivity are not yet clear.

The researchers are optimistic that this study will help provide a variety of preventative or therapeutic approaches to help reduce pain in spinal cord injury victims. But also, the possibility of developing drugs that decrease the amount of acrolein in the body.

It should be noted that acrolein is found naturally in the body and acts as a way for producing pain. This study is the first to show that acrolein from an external source such as cigarette smoke can further increase pain levels.

“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,” said Riyi Shi.