Mini-Science 2012 Q&A: “The chemical conquest of pain” and “How the mind can alter pain”
At the conclusion of each Mini-Science lecture, audience members submit their questions to the evening’s presenter, who answers as many as possible on the spot. Some of the best answered or unanswered questions are sent to the presenter for posting here. Here are questions from the first two lectures.
From Professor Joe Schwarcz’s talk, “The chemical conquest of pain”, March 28, 2012:
Q: Can you please tell us a little bit about codeine?
A: Codeine is an analog of morphine and comes from the poppy plant. It is less addictive than morphine but also less effective as a pain killer. Codeine, along with all other opiates, has side effects on the gastro-intestinal tract, including constipation. Codeine can be found in combinations with other opiates.
Q: Can you expand a bit on “Dosage and Toxicology”?
A: The classic statement is that “the dose makes the poison”. Everything is potentially toxic if the dose is high enough. High enough intakes of salt or even water can even kill you. If you like an aspirin, your headache will not go away, if you take 2 aspirin tablets, your headache will go away, and if you take a whole bottle of aspirin, you will go away. Every different substance has a different chemical profile. We can measure the LD50, which is the amount of a substance that will kill 50% of the rats under study.
Q: Why don’t we make endorphin pills?
A: The structure of endorphins is known. They are polypeptides, which are amino acids joined in a chain. As a pill, they would be hydrolyzed by juices in the stomach. This is also why it is nonsense to take polypeptide supplements because they will not be absorbed into the blood stream. An injectable form could be possible, but then it would not be very different from morphine.
Q: What is the best way to generate our own endorphins?
A: Running and exercise will do that. Going into war and getting shot will also do that.
From Professor Catherine Bushnell’s talk, “How the mind can alter pain”, April 4, 2012:
Q: If placebo reduces brain pain activation, how long does it continue to work?
A: Placebo effects can last a really long time. For example, people use deep brain stimulation for pain relief, and this has the potential of having a strong placebo effect. In a study, people that had successful relief for many years tried some different parameters of stimulation. The stimulators were turned off but they thought they were getting stimulation. The placebo stimulation was more powerful for some patients than actual stimulation. Some patients still felt a tingling sensation, and some patients even said to turn it off as it was too much. Thus it was placebo but they have been having it for years and years. Placebo that is good is self-reinforcing, strengthens your expectation and lasts a long time.
Q: Do people know the cause of Fibromyalgia and if it can be helped? Is there way to reverse gray matter loss?
A: Fibromyalgia involves pain over large parts of your body, and there are multiple causes that can lead to that. There is a core of patients where it is a dysfunction in modulatory system in the brain. Neurotransmitters involved in modulatory systems can be used to reduce pain at a lower dose than they are needed to counter-act depression. Anti-epileptic drugs block hyperactivity in the brain and work better than opiates. The idea is that fibromyalgia patients have hyperactivity in the brain, and modulatory systems are not working as well and these drugs strengthen this modulatory system. The current hypothesis is that the brain is more the cause of the pain than the muscles.
Q: How does anxiety turn into pain and how can this be treated?
A: It is in dispute as to whether anxiety turns into pain. Anxiety enhances pain and pain creates anxiety. Rats given pain for 3 months over their 2 year lifespan became quite anxious. A rat that is brave will explore, and an anxious rat will hide. Months after they develop pain, the pain can lead to this anxiety that is observed.
Q: Do you believe that grey matter of long time empathetic care givers will decrease just as for chronic sufferers?
Q: If you improve your memory and as a result have a thicker cortex, would you have improved tolerance of pain?
Professor Bushnell remarked that these two questions would make really good research projects! Here are some articles on the grey matter and pain to serve as background reading.
Zen Meditation: Thicker Brains Fend Off Pain (ScienceDaily, February 24, 2010)
Study Shows Meditation Changes Brain Structure in Just 8 Weeks (familyhealthguide.co.uk)
Sharing Other People’s Pain (The Brain from Top to Bottom, http://thebrain.mcgill.ca)
Please visit the Mini-Science website for more information about the lecture series.