3 ms·

Doesn't seem that surprising. Receptors and transmitters are highly conserved across the evolutionary hierarchy. Going the other way, there's plenty of molecule

Doesn't seem that surprising. Receptors and transmitters are highly conserved across the evolutionary hierarchy. Going the other way, there's plenty of molecules from plants and fungi that affect the human nervous system.

dnautics 6y ago
But I think the point is that a bunch of anaesthetics (like halocarbon anaesthetics) very much don't bind to receptor sites in ion channels. One running hypothesis IIRC is that they intercalate into the membranes and alter their membrane fluidity... Then underpants gnomes... Then "reduced ion channel activity". Iirc We know it's not something more obvious like "conductivity of the membrane" because that's easy to measure and the effect is not enough to explain the observation.
krisoft 6y ago
> “Going the other way, there's plenty of molecules from plants and fungi that affect the human nervous system.” That is true. On the other hand it sounds like you are saying it is because “ Receptors and transmitters are highly conserved across the evolutionary hierarchy”. The most commonly used explanation for poisonous plants and fungi is that they make these chemicals as a defence mechanism. The mamal eats the thing, the mamal has a bad time and learns to avoid eating the thing. The thing thrives, which provides positive selection pressure for the fungi/plant which can make nasty chemicals. So it is not an accident that mamals react to the secreted chemicals, and it is not because “transmitters are conserved” or something like that.
CamperBob2 6y ago
In general, it doesn't seem surprising that exposing carnivorous plants to large amounts of random chemicals causes them to stop moving, at least while the chemicals are present. In addition to trying lots of similar substances that don't have anesthetic properties in animals, it would be interesting to try xenon, which is all but inert chemically but still works as an anesthetic. Interesting (and more up to date) article here: https://theconversation.com/science-lesson-how-anesthetics-work-and-why-xenons-perfect-83744 https://theconversation.com/science-lesson-how-anesthetics-w...
mrob 6y ago
Ctenophora (comb jellies) are animals but they have very strange nervous systems: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334147/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334147/ "Finally, metabolomic and pharmacological data failed to detect either the presence or any physiological action of serotonin, dopamine, noradrenaline, adrenaline, octopamine, acetylcholine or histamine – consistent with the hypothesis that ctenophore neural systems evolved independently from those in other animals."
hinkley 6y ago
Animals are basically jumped-up fungi, so anything that plants figured out before fungi diverged might show up in the animal kingdom. And some things are important enough that they've evolved several different times. At the bottom it's all chemistry and quantum mechanics. If you can make a chlorine or an iron atom do something interesting, nature will find a way to make that happen.

dnautics 6y ago

But I think the point is that a bunch of anaesthetics (like halocarbon anaesthetics) very much don't bind to receptor sites in ion channels. One running hypothesis IIRC is that they intercalate into the membranes and alter their membrane fluidity... Then underpants gnomes... Then "reduced ion channel activity". Iirc We know it's not something more obvious like "conductivity of the membrane" because that's easy to measure and the effect is not enough to explain the observation.

krisoft 6y ago

> “Going the other way, there's plenty of molecules from plants and fungi that affect the human nervous system.” That is true. On the other hand it sounds like you are saying it is because “ Receptors and transmitters are highly conserved across the evolutionary hierarchy”. The most commonly used explanation for poisonous plants and fungi is that they make these chemicals as a defence mechanism. The mamal eats the thing, the mamal has a bad time and learns to avoid eating the thing. The thing thrives, which provides positive selection pressure for the fungi/plant which can make nasty chemicals. So it is not an accident that mamals react to the secreted chemicals, and it is not because “transmitters are conserved” or something like that.

CamperBob2 6y ago

In general, it doesn't seem surprising that exposing carnivorous plants to large amounts of random chemicals causes them to stop moving, at least while the chemicals are present. In addition to trying lots of similar substances that don't have anesthetic properties in animals, it would be interesting to try xenon, which is all but inert chemically but still works as an anesthetic. Interesting (and more up to date) article here: https://theconversation.com/science-lesson-how-anesthetics-work-and-why-xenons-perfect-83744 https://theconversation.com/science-lesson-how-anesthetics-w...

mrob 6y ago

Ctenophora (comb jellies) are animals but they have very strange nervous systems: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334147/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334147/ "Finally, metabolomic and pharmacological data failed to detect either the presence or any physiological action of serotonin, dopamine, noradrenaline, adrenaline, octopamine, acetylcholine or histamine – consistent with the hypothesis that ctenophore neural systems evolved independently from those in other animals."

hinkley 6y ago

Animals are basically jumped-up fungi, so anything that plants figured out before fungi diverged might show up in the animal kingdom. And some things are important enough that they've evolved several different times. At the bottom it's all chemistry and quantum mechanics. If you can make a chlorine or an iron atom do something interesting, nature will find a way to make that happen.