Mini-Science 2012 Q&A: “The pain-reward connection”

Mini-Science logoAt 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. Here are some of the best questions from Dr. Petra Schweinhardt’s May 9 talk, “The pain-reward connection.”

Q: Why are opioids released higher up in the brain?

A: Opioids are any derivatives, natural or synthetic, of opium or morphine or any substance that has their effects. They’re released in response to a rewarding stimulus and bring about the sense of pleasure. We don’t know whether this decreases pain or whether pain is decreased by a more traditional method. People with chronic pain have chronically overactive endogenous opioid system. Too many opioids over time make them less sensitive to the opioids released by the body or ones we administer.

Q: How can I enjoy my hip pain?

A: Acceptance can help in coping with pain. We have to first accept the things that we cannot change, such as pain, and then once we accept it we have to adjust our goals. In chronic pain situations, patients know the pain will be there for the rest of their lives and they are counseled to do something rewarding despite having pain. It is normal to be frustrated and depressed by chronic pain because we lose abilities and skills. We have found that people with chronic pain take up alternatives such as hobbies, and this gives them pleasure and relieves pain. Think of a hobby or activity that is realistic and feasible with your hip pain.

Q: What about patients who have problems with their dopamine system, such as Parkinson’s syndrome, have they been used in your studies?

A: People with Parkinson’s disease have less dopamine and are more sensitive to pain. In contrast, people with schizophrenia, considered to be the opposite side of the coin, have more dopamine and are shown to be less sensitive to pain. This shows that dopamine is inversely related to pain sensitivity. But the data is “pretty dirty”. We are finding that dopamine isn’t directly linked to how sensitive someone is to pain but indicates what they will do about the pain. For instance, the motivational role of dopamine is more powerful than the reward process. There has been a popular misconception that dopamine directly influences pain sensitivity or is actually inhibiting pain. However, this doesn’t fit at all with some imaging data that has shown that a lot of dopamine is released in the brain in response to pain. We find that the more painful people find the stimulation, the more dopamine is released. If dopamine was inhibiting pain that would not make sense. Now with new thinking about the motivational role of dopamine this makes sense, that is, the more pain you have, the more you want to do something about this pain.

Q: Is “no pain” not enough of a reward in your experiments?

A: That’s an interesting question. It goes along with the question of whether pain relief itself is a reward. It is a different type of reward – it is an intrinsic reward. Fundamentally it seems that pain relief has many of the same rewarding properties as any other reward.

Please visit the Mini-Science website for more information about the lecture series.

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