According to this CNN video, our brains produce opioids in response to pain. Obviously, the brain doesn’t release enough opioids to really kill the pain, but why don’t people who have, say, broken a wrist, feel somewhat better a few moments after the injury, when the brain has presumably released opioids?
The video also says taking opioid medications prevents our brains from releasing their own opioids. Does this mean someone who’s used a lot of opioids but isn’t on them at the time of an injury would feel more pain than someone who’s never taken an opioid? I realize pain perception is subjective, but there must be some way of measuring this.
Natural (endogenous) opioids produced internally are not identical to synthetic opioids introduced from the outside (such as heroin or morphine).
It turns out that they produce different effects. Endogenous opioids for example are not addictive. And an endogenous opioid may take over a minute to stimulate an opioid receptor, while synthetic takes 20 seconds. Synthetic opioids also trigger the receptors differently.
Oh, that’s exciting! As your linked article suggests, we may be able to develop less addictive opioids by mimicking the endogenous/authochthonic flavor. I didn’t know that was a realistic possibility!
Indeed, a broken wrist does not feel that bad immediately after the moment of injury. Later, when the swelling and bruising kick in, and the adrenaline and so forth have worn off, it can hurt worse.
Besides what else has been said, pain consumes opioids. In fact, one emergency treatment for an opioid overdose is to do (normally) painful but non-damaging things to the person to eat up the excess opioids.
I don’t know about broken wrists but when exercising hard enough, you can feel endogenous opioids within 5-10 minutes and it can make a significant difference both in how much pain you experience and how much you care about it. Push it hard enough and you can feel sleepy even though you’re not tired and can keep going.
There are also four different opioid receptor families: Mu (μ),Delta (δ),Kappa (κ),opioid receptor like-1 (ORL1) that have different but overlapping functions and different locations to different degress. And multiple different endogenous opioid peptides that stimulate the different receptors differently. And their varying functions are modulated by other neurotransmitters (sometime co-released, sometimes not) and hormones.
The exact opioid peptide being released, where, with what else and while what else, all matter to what results experientially and behaviorally.
There is subtlety and finesse to the way the body orchestrates and choreographs it all. Not sure anyone actually fully understands the dance. Certainly not me. If you want to really get into the weeds here’s a good start. To the op, as noted, such pain decrease DOES in fact appear to occur to acute injury. One small bit from that article
On another note part of your question had been a thought provoking gotcha by professor I did lab work for as an undergraduate. How do you measure pain perception in a subject.(He was using rats but idea follows through.) Pain perception, nociception, may in fact be impossible to really measure when you are being critically precise. What you can measure is the response to a painful stimulus, nocisponsiveness. You need to be open to the idea that the subject feels as much pain but no longer cares about it as much or is somehow restrained in the response rather than only considering that it perceives it less. The discussion really made an impression on what critical thinking really meant. Damn he was a good teacher!
Thanks for the responses. I was hoping to learn a lot, and I am. I didn’t know, for instance, about the four different opioid receptors. But I think back to injuries I’ve had, and there’s never been a noticeable difference in pain levels shortly after the injury.
Example: I was having yet another eye surgery. This one involved both making cuts and taking stitches in the cornea AND removing an intra-ocular lens (the artificial lens used in cataract surgeries). Because the surgeon ran into scar tissue, the surgery took a lot longer than expected. The gel they use to numb the eye only lasts about 2 hours, and the surgery took almost 3. The pain was horrific, but I’d been warned not to use any of my facial muscles, as the slightest movement could have messed up the surgery, and my arms were secured, so I couldn’t tell anyone. The pain increased as the surgery went on, and nobody knew it because my face was draped.
I’d think the natural opioids would have kicked in after a few minutes and diminished the pain. Instead it got worse and worse. It took all I had not to scream. Shouldn’t the natural opioids have kicked so that I’d have felt slightly less pain?
This is exactly my experience with a broken wrist while skiing. At the moment just after impact, I was acutely aware that I had just broken my wrist. I’m not sure where that awareness came from, but it is pretty much my strongest memory of that moment. I don’t remember much pain at that moment, and then within a couple of minutes, I was able to ski down to the ski patrol hut, just holding my arm tight to my body. By a couple of hours later, the pain was bad, and by that night, I couldn’t sleep because of it.
As far as the eye surgery question, I suspect that both endogenous opioids and subjective pain perception are affected by having pain artificially blocked, and then having the block wear off. That sounds like a really horrifying experience.
You’ve never fallen down, and for what seems like an eternity (but may be a fraction of a second) you’re in so much pain that your breath stops and even the touch of the air HURTS, and then you are capable of getting up and walking, and may even walk around for hours without realizing that you’ve got a broken foot until you’re getting ready for bed and notice the bruise is looking real bad?
I have only done the broken-foot part once, but I do the rest so often that I call it “checking the hardness of the sidewalk: yep, it still is harder than my knees!”
First, the anesthesiologist should have lost any license they hold, and I mean ANY; the rest of the surgical team should have gotten suspended at the very least. And second, you didn’t get hurt in a moment and then the opioids had time to act: you were being hurt continuously. Being punched once <> getting a beating.
I haven’t had a broken foot, but I’ve had other injuries. The first moments of intense pain are also of my mind grappling with the fact I’ve been hurt. The adrenaline rush also kicks in; however, the pain increases after the adrenaline rush is over. Next time I get a significant injury, I’ll try to take note of this stuff.
Thanks for the observation of the surgical experience. It really helps to think of it as getting a beating vs getting punched once! As for the anesthesiologist, etc, well, eye surgery is different than other types. You usually get an IV with a mild sedative to keep you from freaking out because people are cutting your eye. :eek:. (You can’t actually see them, though, as the eye has so many dilating drops and numbing goop, it’s all a blur.) The numbness comes only from topical numbing agents. I guess they don’t use IV painkillers because the topical anesthetic suffices. Maybe more IV sedation would have helped, but they wanted me to be able to follow directions. I’m sure the surgeon must have been aware the topical stuff was due to wear off; my impression was he was trying to hurry. He sounded tense. But he was one of the top corneal surgeons in the US, and I trusted him.
Still, not an experience I’d recommend as a fun party game.
In general, it is true, as the OP suggests, that people taking pain medicine can experience pain doing minor things that a person not taking pain medicines would not perceive as painful.
Pain is almost universally measured using subjective “pain scales” and asking the person. A person in severe pain might have elevated blood pressure, but might not. No single blood test or sign is that reliable. Different people experience the same stimulus very differently, and have different levels of success in natural and exogenous responses to pain. Even placebos or contemplation of “the meaning of pain” can sometimes change it, implying a substantial psychological influence.
