How does ANESTHESIA work in the body?

ANESTHESIA : I don't mean to alarm anyone, but we don't really know exactly how general "Anesthesia" works. We do know that it works, and that it's relatively safe. But scientists are still trying to figure out how all these different chemicals switch out the lights in your brain. ANESTHESIA is a state where you're insensitive to pain and doctors use it so that when they need to operate humans heart or any serious operation. They can turn something invasive and traumatic into a peaceful nap.

There are three types of Anesthesia : [GENERAL ANESTHESIA] is the kind that knocks you out completely, as opposed to [LOCAL ANESTHESIA] which just numbs a part of your body for a while or [TWILIGHT SEDATION] where you're technically conscious but won't remember anything that happened.

Usually GENERAL ANESTHESIA involves a combination of two drugs, The FIRST knocks you out fast and the other one keeps you that way. The ANESTHESIOLOGIST can fine-tune the dosage of the second drug to make sure you don't wake up too early or go too far under. So we know that ANESTHETICS knock you unconscious and we know that they keep you from feeling pain, responding to your environment and almost always from remembering what happened.

Which is a huge plus because feeling and remembering being sliced up and stitched back together would not be pleasant. But Anesthesia is not the same as going to sleep. Some parts of the brain are still active but unlike when you're fully conscious those active parts don't really communicate with each other. The brain patterns of someone under anesthesia don't look like sleep, either. There is no RAPID EYE MOVEMENT or Dreaming under anesthesia.

ANESTHESIA brainwaves actually look a lot like the brainwaves of coma patient, which make sense because anesthesia is a lot like a coma. It's just reversible under a doctor's control. The weird thing is the same Anesthetic state can be brought on by a whole bunch of completely different chemicals.

From the (Nobel Gas Xenon) to big molecules made up of rings of "Carbon". Since all these different anesthetics do similar things, scientists figured they must have something in common and the most obvious one was they almost all dissolve in oils, Oils like the insides of your cell membranes.

For decades, researchers thought that Anesthetics could dissolve in the membranes of your brain cells and disrupt them somehow. But some compounds that are similar to anesthetics and very oil-soluble don't numb pain and some anesthetics aren't very oil-soluble at all.

Instead, these days scientists thing it has more to do with proteins, which have oily patches too. So anesthetics probably bond to proteins in your brain but it's hard to study drugs that bond in an oily environment. Anesthetics bond very weakly to the proteins they can on and it's hard to get them to stick in place for long enough to know exactly where they're stuck.

The best understood anesthetic is also one of the most popular the (PROPOFOL). Propofol binds the receptor for a chemical messenger called GABA which is involved in  controlling sleep and alertness some other things. PROPOFOL helps activate the brain's receptors for GABA and researchers thing it's especially active in the part of the brain that handles sleep.

Here's a chart showing the most common applications for Anesthesia (via University of Toronto):

What we don't know is exactly how that part of the brain controls consciousnesses and how Propofol swithces it off and then back on again as soon as it goes away. But since studies have found that there is also a bunch of other anesthetics that also bind to the GABA receptor researchers thing they are on the right track.

There is one really strange thing we do know : REDHEADS Need more Anesthetic, Doctors have been reporting cases of this for a while and at least one small study showed that redheads need 19% more Anesthetic than people with dark hair. According to the authors of the study, the gene that produces red hair color seems to be related to resistance to anesthetic, especially since it's also been linked to pain sensitivity.

So, we don't really know how General Anesthesia works but it's a good thing that it does and as we study it, we are going to be learning more about how the brain is put together in our next article.