Professor Grace, In lay person’s terms could you tell us how pain gets triggered in a human being?
Pain is a normal response that protects us from harm. For example, the pain experienced from putting your hand on a hot stove encourages you to remove your hand to prevent further damage. That pain is transmitted from nerves in the skin, right through to the brain.
This pain detection system can get messed up when those nerves are injured (e.g. from surgery, diseases like shingles, or injuries), and the changes to this system can outlast healing of the original injury. When that happens, normal things like movement and clothing touching the skin are wrongly interpreted as pain. We collectively call this ‘chronic pain’, and it is estimated to affect 1 in 5 people around the globe.
Again in terms that our readers will be able to grasp, how do pain killers work?
The painkillers on the market right now work by shutting down the nerves that are responsible for sending pain signals.
Please tell us about your research on the use of opioids on rats and how relevant it is to humans?
We’ve found that opioids surprisingly make pain worse in the long-term in rats. We show that opioids produce the normal pain relief while they are being administered to the rats, but once they are taken away, the pain lasts for months longer than the rats that didn’t get the opioid. If the rats had no pain in the first place, then the opioids didn’t have that effect, indicating that it was a biological interaction between the pain signals and the opioid. We’ve shown that this interaction occurs at cells called microglia—which normally support nerves in the spinal cord. The opioids cause the microglia to further mess up the pain detection system, resulting in prolonged pain.
These findings are relevant to humans, because there have been no long-term human studies on the effects of opioids, like we’ve done here. These studies need to be done, because our results suggest that long-term opioids may providing no benefit to some chronic pain patients, and may actually be harmful.
Professor Peter M. Grace with his family / Photo: From archive of Professor Grace
What would you say on the flagrant use of pain killers given that most of them are available over the counter?
Over the counter drugs like codeine could have a similar effect, so people need to keep their healthcare professionals informed about which drugs they are taking. Other drugs like morphine, used in our studies, are only available by prescription. However, the science is now starting to catch up with medical practice, and we need to examine how frequently these drugs are given out, and for how long.
Hippocrates said ‘Let food be your medicine’. What are your thoughts on natural pain killers at home such as turmeric, ginger, cherries, red grapes, hot peppers and coffee for the ‘lesser’ and chronic pains? Are these natural painkillers relevant in these modern times?
If these approaches work for people with chronic pain, then that’s great! However, it can be difficult to consume enough of these foods to get pain relief. But these foods can also teach us a lot about how pain can be treated, by identifying the active ingredients and studying how they work. This approach can provide clues on how to develop new and powerful drugs to treat pain without the addictive properties.
Please tell us about the other areas of your research?
I’m also interested in how exercise and an active lifestyle can help to prevent pain. We’ve shown that rats that exercise in running wheels are protected from chronic pain after an injury. A healthy lifestyle, which includes eating well (as you suggest above) and exercising, may be one way to help prevent chronic pain.
Please tell us about your growing up years, who motivated you into reaching the exalted position you are in?
I grew up in a rural part of Australia and was fortunate that my parents were educated and valued and supported learning. It wasn’t until University that I really discovered my passion for scientific research. I had a number of mentors who really encouraged my scientific and professional development. I owe much of my success to these people.
Our readers who are the youth in many parts of the world obviously look up to the educated elite. May I ask a word of advice for them?
Personally, my successes have often followed a series of failures, because I didn’t give up. I encourage readers to keep persevering towards their goals, especially through failure and disappointment.