Anesthesia in plants?

[anciendaze]

Many of us know that anesthetics can knock us out easily, though I at least don't have to worry about dying, like one person I know personally. "If you torture me, you'll learn nothing, I have a low threshold of death."

Now, researchers have found that anesthetics also paralyze plants, which have no nervous system.

The common factor is voltage-gated ion channels.

You might think this whole business was handled long ago, when anesthesia was discovered. The fact is that anesthetic action of chemicals as simple as diethyl ether has been mostly unexplained.

If the same simple chemicals act the same way in highly-evolved vertebrates and plants I would say the underlying mechanism must be a highly-conserved characteristic, almost by definition, and that means it is doing things that are very important.

How did we get this far without knowing?

 

[Wonko]

We is both really very very stupid, and incredibly arrogant - always a winning combination when it comes to learning things.

 

[Gingergrrl]

The common factor is voltage-gated ion channels.

This is what scares me if I should ever need anesthesia b/c neuros told me to avoid one that blocks the calcium channel b/c of my autoantibody. I think from what you are saying is that plants have the same voltage gated ion channels as humans? (I know nothing about any of this stuff but at least I am aware that I do not know)!

 

[alkt]

trial and error wonderful thing in the medical profession they can always bury their errors.

 

[anciendaze]

This is what scares me if I should ever need anesthesia b/c neuros told me to avoid one that blocks the calcium channel b/c of my autoantibody. I think from what you are saying is that plants have the same voltage gated ion channels as humans? (I know nothing about any of this stuff but at least I am aware that I do not know)!

These are not the same voltage-gated ion channels, but they must have enough common subunits for a small molecule like diethyl ether to fit in and cause similar changes in function. Take a look at the simple structure. You may also find the entry on metabolism, cytochrome and a dehydrogenaze significant. Various cytochromes are highly-conserved by evolution because of important activity in metabolism. We have diseases that show metabolic abnormalities. Sounds interesting.

On a personal level, you can tolerate anesthesia better than at least one person I know. Knowing the mechanism to avoid in your case should be enough for any competent anesthesiologist. There are trickier problems.

 

[Hip]

How did we get this far without knowing?

According to the study cited in the article, the susceptibility of plants to anesthetics was first discovered 140 years ago by Claude Bernard, in around 1878.

I certainly did not know this though; it's very interesting.

 

[Hip]

The common factor is voltage-gated ion channels.

One other area of commonality is microtubules: these are found in animal and plant cells, and one theory by Hameroff and Penrose posits that the phenomenon of conscious is created within the hollow interiors of microtubules.

Rod Eckenhoff showed that anesthetics interact with microtubules, and it has been proposed that anesthetics obliterate conscious by disrupting the functioning of microtubules. And this would work both in animals and plants, since both contain microtubules in their cells.

 

[anciendaze]

According to the study cited in the article, the susceptibility of plants to anesthetics was first discovered 140 years ago by Claude Bernard, in around 1878.

I certainly did not know this though; it's very interesting.

My point was that until recently nobody knew the mechanism for something that is very highly-conserved by evolution. That points to some very important function.

Microtubules are active in many kinds of cells, like those undergoing mitosis. They are also responsible for cell movement, which would cause anesthesia to shut down mobile immune cells. Maybe this happens, but doesn't last long enough to create problems. I think Penrose, like many mathematical physicists, underestimates the complexity and sheer strangeness of living things. There are many examples where life chose to do things in ways that causes face-palm moments. (Example: you have a blind spot in your retina where the optic nerve gets in front of receptors. An octopus has a better design in which the nerve connections are behind the retina.)

Personally, I like the connection with voltage-gated ion channels better. This could be productive, on a human time scale.

 

[Hip]

Personally, I like the connection with voltage-gated ion channels better. This could be productive, on a human time scale.

It's good to have several competing theories to explain the currently unknown mechanism of anesthesia; that usually gives you more chance of eventually finding the actual mechanism.

I think Penrose, like many mathematical physicists, underestimates the complexity and sheer strangeness of living things.

Possibly, I know what you mean; but he has had a lifelong interest in the life sciences, so he does know quite a bit about biology. And Hameroff himself is an anesthesiologist, with a life science background.

It makes sense that quantum computation would be harnessed biological systems, because quantum computers are much more powerful that regular classical computers, especially when performing optimization-type calculations (eg the traveling salesman route optimization problem, in which calculation time explodes exponentially as the problem size increases). You might presume optimization-type calculations would be important in biology (for finding the optimum biological or molecular design).

What I like about the efforts by Penrose and Hameroff is that they are suggesting that microtubules, as well as being the scaffolding of the cell and the transport system of the cell, are also able to perform quantum computation, ie, that microtubules are the place in the cell where quantum computation is harnessed.



Hameroff has proposed an interesting theory of Alzheimer's, based on the idea that microtubules are disrupted in Alzheimer's by tau protein abnormalities (which is known to be the case). If microtubules are indeed the seat of consciousness, then the terrible deficits of mind that appear in Alzheimer's may be directly due to the microtubule disruption.

I have wondered whether the brain fog of ME/CFS might also be due to microtubule disruption. Brain fog seems like a contraction and diminution of consciousness. So quite possibly, this might be due to some ill effects on microtubules.

 

[anciendaze]

Penrose is quite capable of proposing novel ideas that are not even susceptible to testing. Take his book Cycles of Time, a semipopular presentation of Conformal Cyclic Cosmology. His ideas on conformal field theory are interesting, but would imply that all particles are ultimately massless. This is more than a large leap of faith, it runs into a great deal of trouble in connecting it to the bulk of existing physics. The origin of rest mass remains a very big question in physics. Theoreticians have repeatedly felt that the Universe would be simpler if there were no mass.

He would also claim to be able to extend retrodictions beyond the Big Bang. At this point that seems completely untestable. The idea of a vanishing Weyl tensor in the Big Bang, didn't go over well with Hawking, (who also noted that this is a homophone of "vile tensor". A look at the math should convince anyone that mess really is vile.) Hawking's recent work indicates that information is not destroyed in Black Holes, which ties in with modern theories of entropic gravity. I believe this runs counter to Penrose's CCC, but will defer to younger minds on the question.

Penrose is extremely smart, even at his present age, but is better at stimulating discussion and proposing ideas to knock down instead of resolving questions. He was in the thick of the debate about Black Holes at the time when Jacob Bekenstein noted a connection between area of event horizon and entropy, which ultimately led Hawking to predict they would emit radiation and eventually evaporate. He was there at the right time, and smart enough, but missed this first advance in the direction of quantum gravity, probably because the idea didn't meet his standards for elegance. (The things he was working on instead were quite deep, look up twistor theory. This is elegant, but very difficult to apply to anything. I've been waiting to hear great things from this research for about 50 years.)

Much of what he says about microtubules is also true of a range of molecular structures in cells, including ion channels. Without quantum mechanics none of this would work, and I can testify that quantum mechanics is really strange, by any common-sense standards.

 

[Hip]

Take his book Cycles of Time, a semipopular presentation of Conformal Cyclic Cosmology.

I know of this theory and it basic idea, but have not read any new popular science physics books for about 12 years now since getting ME/CFS, as brain fog makes enjoying and getting into such books too difficult. So unfortunately I don't know much about any newer ideas in physics; I just know the stuff I'd read prior to developing ME/CFS.

I was very impressed with the fact that Penrose's twistor theory, an algebra he proposed in the 1960 and which for many decades lay lost in the wilderness, was mathematically proved by Edward Witten to be an equivalent way to formulate string theory, which then reinvigorated interest in twistor algebra. Witten's mathematical proof also demonstrated that the three different versions of string theory in use are all equivalent formulations of the same thing, and are equivalent to twistor theory.

Much of what he says about microtubules is also true of a range of molecular structures in cells, including ion channels. Without quantum mechanics none of this would work

Certainly quantum mechanics is behind all molecular interactions in biology, but these quantum effects remain confined to local microscopic locations. At normal temperatures, you usually only ever have microscopic quantum effects, but never macroscopic ones like superconductivity and superfluidity where quantum states extend over macroscopic distances. Those macroscopic states normally require low temperatures.

Whereas Penrose and Hameroff propose microtubules have the ability to all link together to create a large-scale macroscopic quantum state that extends over the entire brain even at body temperature. This macroscopic quantum state is linked in locally to the microtubules in each cell, and in this way, connects to individual neurons and "wires" these neurons all together via the brain-wide quantum state. This is how they propose all mental events are bound together and integrated into a unified conscious experience.

So in their theory, Penrose and Hameroff suggest that nature has figured out a way to create and exploit large-scale macroscopic quantum state at normal body temperatures.

 

[anciendaze]

There are multiple speculations in your last post presented as facts. I can only say that suppositions about localization of quantum effects outside of microtubules should be suspect. We already know of entanglement outside of cryogenic experiments spanning significantly more than the size of a human brain. Quantum encryption is an example. Here's an example of a proof of concept without cryogenics.

Nature might have figured out how to do this with microtubules, or many other biological structures.

On the subject of twistors, if you look at the math you will see that twistors are commonly represented with a pair of spinors. Spinor algebra was worked out in the 1930s, and calculus based on this is standard in Quantum ElectroDynamics (punned as QED), which works in 3-spacelike and 1-timelike dimension, even if physicists don't always talk about spinors. Mostly they work with matrices and tensors, which have been around long enough to become familiar. You can represent one hell of a lot of things in an 8-dimensional space that twistors live in, some of which may well correspond to real physics, though most will not. You can also find physical theories using octonions, which are also 8-dimensional. There ought to be a correspondence between these theories, but this is beyond me.

I'm not belittling Penrose's mathematical accomplishment, I'm just pointing out that it proved very hard to apply. Witten's original equivalence proof of various string theories did not, to the best of my memory, rely on the twistor formulation. Some connection between string theory and experimental tests would also be nice, before claiming a major advance.

At present multiple string theories have problems explaining the origin of a "background" against which wiggling strings are measured, the origin of mass, and the limitation to three generations of elementary particles. If there were more, there are thermodynamic arguments that the present Universe should not exist.

I'm always concerned about investigating such questions, in case I should prove that the Universe cannot exist.

 

[Hip]

I can only say that suppositions about localization of quantum effects outside of microtubules should be suspect. We already know of entanglement outside of cryogenic experiments spanning significantly more than the size of a human brain.

Actually I am not sure if I got that right about the Penrose and Hameroff theory positing that microtubules create a macroscopic quantum state across the brain. But I think these individual microtubules across the brain are posited to communicate and interconnect with each other by some means, as that's how they say their theory solves the so-called binding problem of consciousness (binding problem = explaining how mental events are bound together and integrated into a unified conscious experience).

I just Googled, but I can't seem to find the proposed mechanism by which these individual microtubules are interconnected.

The Penrose and Hameroff theory is also linked to the gamma waves found in the brain, which are around 40 Hz; they propose that the Orch-OR process (orchestrated wave function collapse) in microtubules give 40 conscious moments per second, with each moment caused by a wave function collapse. They think this may tie in with the gamma waves. So 40 Hz is the normal "frame rate" of consciousness. Experienced meditators though are measured to have higher gamma wave frequencies, eg, 80 Hz, and are thus thought to have a higher rate of conscious moments per second.

Penrose and Hameroff though certainly theorize that a macroscopic quantum state exists within the hollow interior of the microtubules. I believe the quantum vibrations in microtubules have been experimentally confirmed now. Note that it was Stuart Hameroff's idea that quantum states may exist within microtubules, and he proposed this to Roger Penrose. Penrose thought quantum mechanical systems might be behind consciousness and might be harnessed by the brain, but did not have any good ideas about where these quantum systems would reside in the brain, until he teamed up with Hameroff.

 

[anciendaze]

Microtubules are very active in dividing eukaryotic cells during mitosis. They are also very active during movement of organisms like amoebas. You can argue that these are too small to exhibit much consciousness. What about larger aggregations of such organisms as slime molds? You can argue that these show no signs of consciousness, until presented with evidence of them solving problems. Here are molds solving more difficult problems.

How do you argue that humans possess consciousness because of microtubules without granting consciousness, and possible superiority, to slime molds?

This is the kind of question I try to avoid. I am much more sympathetic to Penrose's criticism of artificial intelligence. At present I don't think we have much idea about what we mean by consciousness. There are certainly very complex processes taking place outside awareness in people we are all certain are conscious, (except for hard-core behaviorists who don't believe in consciousness.)

 

[Hip]

Microtubules are very active in dividing eukaryotic cells during mitosis. They are also very active during movement of organisms like amoebas. You can argue that these are too small to exhibit much consciousness. What about larger aggregations of such organisms as slime molds? You can argue that these show no signs of consciousness, until presented with evidence of them solving problems. Here are molds solving more difficult problems.

Yes, those maze-solving abilities of slime molds are incredible.

Hameroff has tentatively suggested that the posited information-processing capabilities of microtubules may possibly constitute the nervous system of a cell. Whether microtubules might also endow those single cells with some elementary consciousness properties is another question; I don't think we can answer this question until we get a better understanding and definition of consciousness.

But even if single cells do have elementary consciousness properties, this I expect would in some sense be a weaker manifestation of consciousness compared to a conglomerate of cells all linked together and operating in unison, as is posited to occur in the brain. It's the gamma wave synchrony that is posited to be involved in binding these microtubules together.



I was interested in the study of consciousness, and my own feeling was that consciousness may be best understood in very abstract mathematical terms. Even if Hameroff and Penrose are right and microtubules are the source of human consciousness, microtubules would just be a specific physical implementation that harnesses the power of consciousness. Alien species from another planet might also be conscious, but their consciousness may come from an entirely different physical implementation.

So we really need to understand what consciousness might be in more abstract terms. I think, as Penrose's seminal book "The Emperor's New Mind" hints at, an understanding of consciousness might come from studying areas such as the Turing limit on computation, and P versus NP computations.

 

[anciendaze]

One tiny objection to that last statement. The P = NP? question is about algorithms. For those who use the terminology precisely an algorithm is an explicit means of computation which will always give a correct answer for a stated well-defined problem in a finite amount of time, even if that answer might be "there is no answer." For P and NP it is possible to bound that time based on problem size without actually running the computation to find out how long it takes.

Human problem solving much more resembles probabilistic computation like Monte Carlo or Los Vegas methods. This is an example of a broader definition of "algorithm" than that used in the theory of P and NP.

What goes on inside humans is far from explicit, and may or may not present a correct answer, or indeed any answer, in a finite time. Most problems we deal with are not well-defined, and many answers we come up with are demonstrably wrong. Loosening restrictions this way could allow existing machine intelligence to be considered equal or superior to human intelligence, even though the machines or programs don't even know they exist unless you build in rules for this purpose. (Something seems wrong about having to do this if you are really dealing with intelligence. Infants who don't know much about anything else are well aware of "me, me, me".)