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Medicine Science

Scientists Change Our Understanding of How Anaesthesia Messes With the Brain (sciencealert.com) 92

schwit1 shares a report from ScienceAlert: It's crazy to think that we still don't quite understand the mechanism behind one of the most common medical interventions -- general anaesthetic. But researchers in Australia just got a step closer by discovering that one of the most commonly used anesthetic drugs doesn't just put us to sleep; it also disrupts communication between brain cells. The team investigated the drug propofol, a super-popular option for surgeries worldwide. A potent sedative, the drug is thought to put us to sleep through its effect on the GABA neurotransmitter system, the main regulator of our sleep-and-wake cycles in the brain. But anyone who's been "put under" will know that waking up from a general anesthetic feels rather different from your usual morning grogginess. On top of that, some people can experience serious side-effects, so scientists have been trying to figure out what else the drugs might be doing in the brain.

Using live neuron cell samples from rats and fruit flies, the researchers were able to track neurotransmitter activity thanks to a super-resolution microscope, and discovered that propofol messes with a key protein that nerve cells use to communicate with each other. This protein, called syntaxin1A, isn't just found in animal models - people have it, too. And it looks like the anesthetic drug puts the brakes on this protein, making otherwise normal brain cell connections sluggish, at least for a while. The researchers think this disruption could be key to how propofol allows for pain-free surgery to take place - first it knocks us out as a normal sleeping pill would, and then takes things up a notch by disrupting brain connectivity.
The research has been published in Cell Reports.
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Scientists Change Our Understanding of How Anaesthesia Messes With the Brain

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  • Stitch in time (Score:5, Interesting)

    by Camel Pilot ( 78781 ) on Thursday January 11, 2018 @08:58PM (#55912135) Homepage Journal

    I friend of mine just had a colonoscopy and was laying on his side looking at a pattern on the wall just before being given propofol. He woke up looking at the same pattern and the Doc said everything was normal. He accused the Doc of haven't done anything and was conducting some fraud because he hadn't any sense any lapse in time. Propofol is like that.

    • I just had a sedative, so I got to watch all the twists and turns on a video screen.

      • by Kokuyo ( 549451 )

        Hag, you Noob! I had to drive home and did it without any drugs! I think that was about my second one... the third I did put-under again because man, that sure was uncomfortable...

        • by Kokuyo ( 549451 )

          That should have been. a "Hah" up there... no insult was intended... except for the noob, of course :D.

        • by gay358 ( 770596 )

          It seems that in USA there is often/typically some kind of anesthesia with colonoscopies, but outside USA it is much less common, unless the patient has some kind of phobia or very painful experiences in previous examinations. I have had once colonoscopy and I don't think it was that hard to handle, expect drinking large amount of not that great tasting medicine to empty the bowel which took some effort. I have also had twice gastroscopy and it was much more unpleasant than colonoscopy, even though gastrosc

          • My colonoscopy was the least comfortable I've ever been in a medical situation without something being seriously wrong with me.

    • Yup, it's pretty awesome! I highly recommend it!
  • by dlleigh ( 313922 ) on Thursday January 11, 2018 @09:01PM (#55912151)

    I had minor surgery a few years ago and they used propofol as part of the anesthesia.

    I woke up feeling amazingly refreshed and relaxed. I can kinda see why Michael Jackson was using propofol every night... until it killed him.

    Physicians like to too because of its memory blocking effect. There's less chance of malpractice suits if your patient can't remember anything, even from right before and right after the surgery when they aren't actually unconscious.

    • by rfengr ( 910026 )
      Ditto. Had surgery as a kid in the 70’s and woke up vomiting. Had it again a few years ago, a woke up feeling feeling awesome. Great advancement since then.
      • Had it again a few years ago, a woke up feeling feeling awesome. Great advancement since then.

        It seems propofol is not quite 100% perfect yet.

        • by rfengr ( 910026 )
          Well the strange thing is I had no memory of being wheeled into the OR, until 2 weeks later, then BAM, a sudden flash of full memory. The stuff messes with your memory.
    • by mveloso ( 325617 )

      If propofol could be put into a pill I'd take tons. Taking it was the most refreshing experience ever.

    • by demonlapin ( 527802 ) on Thursday January 11, 2018 @11:25PM (#55912713) Homepage Journal
      Propofol also has a very short duration of action. The "fog of general anesthesia" is much more likely to be caused by the benzodiazepine sedatives that most will get prior to actual induction of anesthesia. Those benzos - classically, Valium (diazepam); today, usually Versed (midazolam) - are in the same class as Rohypnol (flunitrazepam, but famous as "roofies"). They're very good for treating acute anxiety, but they're also addictive, and seriously interfere with memory formation.

      I'm an anesthesiologist, and unless someone is really climbing the walls with anxiety (not, actually, all that common), I don't give benzos. I give a solid dose of long-acting opioids right up front, and that's it. The only time I've ever had Versed, I got an eight-hour gap in my memory. Don't remember a thing. Rather obvious why it became popular as a "date-rape drug".

      We do use propofol for colonoscopies, and it's a great drug for that, but most general anesthetics are conducted with gas anesthetics - they are cheaper and they are very easily monitored (we can easily see how much you're breathing in and out, and thus infer how likely you are to have any awareness). In most cases, propofol is used only to induce anesthesia - to make you unconscious so that you can be intubated. As soon as the breathing tube is in, the gas is turned on, and that's what you're waking up from. The advantage there is that, as with alcohol, people tend to get disinhibited before they lose consciousness. You don't want someone without a secured airway flailing around on the OR table (they might fall off). A slug of propofol takes them from conscious to comatose in a matter of seconds. By the time it wears off, the gas has kicked in.
      • by Kokuyo ( 549451 )

        Sounds a bit boring.

        I wonder what the stuff was they gave me before removing a fistula. Felt like I was only half as heavy and all tingly. I felt less inhibited, sure, but only a tad less than when I am tipsy from alcohol.

        I just enjoyed talking about stupid stuff and found that funnier than normal, however I was clearly aware of that fact. And I believe (though can't prove it) I could have stopped if the situation had demanded it. Since I was lying belly-down on an operation. table of some sort, I just figu

      • by Anonymous Coward

        I had that shit for a colonoscopy. While I was under I had the craziest dreams.....

        I dreamed that the US elected a retarded reality tv star as President, then started thinking about maybe electing another TV star who's only good for telling stay at home mothers what shoes to buy or books to read, as a replacement.
        Fucked up weirdos were deciding they were girls one day and boys the next. A fat psycho in North Korea was going to start a war because he didnt like the names the TV reality star US President was

      • by twdorris ( 29395 ) on Friday January 12, 2018 @07:43AM (#55913875)

        Posts like this are why I still come to Slashdot. This place is still the best resource I've found where people with such a diverse set of highly skilled talents can all post about experiences and information that they are intimately familiar with in their respective trades and we all learn / grow from that. Thanks!

    • by rwven ( 663186 )

      The amnesia effect with that stuff is insane. Every time I've had it I remember being wheeled toward the OR, and then I'm sitting next to the nurse in recovery. Then for the next 6-12 hours, I may or may not remember anything that happens to me. I don't remember entering the OR, counting down, etc.

      It kinda weirds me out that I was conscious and doing something at one point that I now have no recollection of at all.

    • by Megol ( 3135005 )

      Memory blocking? Haven't heard it described as having that effect, are you sure that isn't due to some other drug used in conjunction with the propofol? It is often used together with other drugs including hypnotics that can cause retrograde amnesia.

      My experience is completely different (and I've had a lot of minor operations using it) as the injection of it is followed by a spreading mildly painful cold sensation with an increasing mental "noise" until losing consciousness. The experience lasts for a short

    • There's less chance of malpractice suits if your patient can't remember anything

      While this is the norm it is also imperfect. Most of my time directly after my wisdom teeth surgery is a haze. But the bit I do remember is waking up briefly looking at 2 people with masks who suddenly said "fuck he's awake!".

      Lasted 2 seconds, and that memory is permanently burned in my brain. It was like a movie complete with the dental surgeon holding a curved set of pliers.

    • by gay358 ( 770596 )

      BTW, there is some evidence that propofol reduces sleep debt, unlike normal anesthesia:

      https://www.uchicagomedicine.o... [uchicagomedicine.org]

      "We concluded that the need to sleep was not accumulating inside rats that received propofol and therefore either propofol was preventing their "sleep debt" from building up or propofol was, like sleep, helping rats to discharge it."

      "So we then allowed rats to sleep naturally or gave them a period of sedation with propofol and looked to see how they recover. What we found is that recovery

    • It depends on the person. For me, I wake up like I had a good night sleep, until it fully wears off and I pass out from exhaustion. My Wife on the other-hand is miserable for 72 hours after. And is often violent to the staff when she wakes up.

  • by sgage ( 109086 ) on Thursday January 11, 2018 @09:20PM (#55912225)

    "This protein, called syntaxin1A, isn't just found in animal models - people have it, too."

    You f-ing idiot, people are animals - capiche? Not demigods, not brains in vat (as much as some geeks would love that). Animals. Meat. We are great apes. Like gorillas and chimps and orangs and so forth. That's what makes life interesting ;-)

    • by Baron_Yam ( 643147 ) on Thursday January 11, 2018 @09:24PM (#55912253)

      >people are animals - capiche?

      And this is not pedantry at all. For most of human history, we've considered ourselves divinely special and separate from nature, and that attitude causes all sorts of problems.

      WE ARE JUST ANIMALS. Animals with the most intelligent brains on the planet, but animals nonetheless.

      I'm pretty sure most medical researchers understand that and simply use the term as a convenience, but they really ought not to.

      • by kwack ( 98701 )

        FYI, "animal models" doesn't mean animals in general. The term refers to various laboratory strains in widespread research use. Such as black6 mice or fruit flies.

    • by JoshuaZ ( 1134087 ) on Thursday January 11, 2018 @09:28PM (#55912263) Homepage
      They were more careful than you give them credit for here. The quote explicitly says "animal models" so they weren't talking about all animals, just those used as model organisms.
      • by sgage ( 109086 )

        I wasn't so much dissing the researchers, just the submitter of the article. And science 'journalism' in general just really sucks.

    • by HiThere ( 15173 )

      Yeah, but there are many things that are characteristics of some animals, e.g. mice, that don't apply to people. So it's useful info to say that this protein is also present in people. (They didn't say it was present in all animals, maybe it isn't.)

  • Everything is just 'thuper!
  • Probably similar to the same way TV messes with the brain.
  • I now have a bit more of an understanding of why anesthesiology is such an art - not enough of this stuff and you may paralyze someone without knocking them unconscious for a surgery. Too much, and you dangerously dampen the parts of the brainstem that control breathing and cardiac rhythms. I'm curious though as to why consciousness goes before breathing does...if these drugs are given intravenously, wouldn't they diffuse to all parts of the brain equally, and cause just as much consciousness loss as brea
    • by Anonymous Coward

      Breathing is autonomous, whereas consciousness isn't.
      Essentially consciousness -- outside area of brain, breathing -- inside are of brain.
      The core functions are the critical ones. Don't breathe, die, go unconscious well maybe you get left alone by the coyotes.

    • Re:Delicate dosing (Score:5, Informative)

      by demonlapin ( 527802 ) on Friday January 12, 2018 @12:09AM (#55912865) Homepage Journal
      We generally don't care if you stop breathing - it's sort of our thing to breathe for you. Consciousness requires a great deal more coordination than the simple breathing centers, though. The same reason explains why anesthetics make you lose vision as a sense before you lose hearing - it's a more processing-intensive sense.

      As for cardiac rhythms, gas anesthetics are arrhythmogenic, but it's usually not a problem. Spinals - as are given for most cesarean sections - are more likely to produce slow heart rates, as they disable the autonomic nerves as well as the sensory ones. However, we have drugs for that.
  • I had a major spinal surgery about 10 years ago after falling of a cliff and smashing a vertibrae. The last thing I remember from the operation was really paying attention when they gave me an injection on our way into the operating room, and that's it. Woke up feeling pretty good for having had my spine messed with for over 4 hours. It still bugs me that I can't put my finger on the experience; I have no idea if it was really that instant or if I simply don't remember.
  • Robin Williams had a great blurb about Propofol. I've had it a few times myself. It's true.
    https://www.youtube.com/watch?... [youtube.com]
  • I've been put under on that stuff a handful of times. Each time it was the same time travel experience. The first time I woke up from having a tendon fixed and I asked the nurse who suddenly appeared at my side as I was being wheeled down to recovery "What the heck was that? Am I ready for surgery?" "You're done." I lift up my arm and marvel at that half-cast on my wrist.

    That stuff is amazing. I was allowed to push the plunger on the syringe once during a surgery a few years later. The staff said I got one

    • I always try to remember, when coming out of anesthetic, to say something like 'what year is it? WHAT YEAR?!'

      Every time I mention that, I'm reminded about how lucky we are to live in a day and age when we can treat invasive surgery so casually, and when it's perfectly possible for somebody to have gone through five or six of these things for relatively minor ailments.

      Also, even more lucky, that I live in a country where I don't go bankrupt just for want to, say, not suffer from painful gall stones for the r

  • by peppepz ( 1311345 ) on Friday January 12, 2018 @02:13AM (#55913167)
    Can we do without super childish language at least here on Slashdot? Super pretty please.
  • by eWarz ( 610883 ) on Friday January 12, 2018 @02:36AM (#55913211)
    I almost died in April 2017 of septic shock. During that time, medical staff assumed I was unconscious and unable to recollect a single thing. I had 4 surgeries and I was on a ventilator for many days and I was on enough drugs to kill an elephant. I remembered everything. Including some VERY personal conversations from certain staff members. It was all so vivid. I can't discuss most of it thanks to an ongoing malpractice suit against the hospital that caused the issue to begin with...however. Never assume your loved one doesn't hear you. They do. They hear you. They also hear the medical staff talking about their so called 'day' as they turn you, change various 'things', etc.'
    • by Anonymous Coward

      So because you may have a l had some awareness that they can't predict or necessarily detect but they kept you alive and turned you to prevent bedsores your are suing them. This is an excellent example of what is fucked up about American healthcare. Do you expect the staff not to speak when they are in your room would you rather they just be drones? I'm not saying that awareness is desired or that it isn't traumatic but how about they get you counseling and you stop the suit against the people who saved

  • by Anonymous Coward

    It makes sense to me that anesthetics do more than just "put you to sleep".

    We use them to humanely perform painful procedures of course. If all they did was to activate unconsciousness, why wouldn't the pain wake you up? Even if you assume the anesthetic is actively and continuously promoting unconsciousness, which is almost certainly true.

    Pain is an ancient survival mechanism. Even primitive organisms have pain reflexes. I doubt that unconsciousness, which by definition is a high level function concern

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