Paralysing the somatic nervous system

  • #1
In the movie Law Abiding Citizen, theres a scene where a guy gets paralysed by a puffer fish toxin I think it was (maybe tetrodotoxin) and the guy who paralysed him explained that "the toxin completely disables your ability to move your muscles but it leaves all the other neurological functions intact so you feel everything". Are there drugs that will cause paralysis without analgesia? Tetrodotoxin causes paralysis but its mechanism of action is it blocks voltage gated sodium channels which is the same thing that local anasthetics like procaine does so I'm guessing it completely numbs the person so they can't feel any pain. Curare paralyses both the somatic and autonomic nervous system and if I'm not mistaken, it does this by blocking ACh receptors. If I'm not mistaken, curare is actually used as an anesthetic so I'm guessing it numbs the patients ability to feel pain. The idea of being paralysed but being able to feel pain is a bit disturbing to me. I get sleep paralysis regularly and I can feel physical sensations while in it. I can pull myself out of sleep paralysis but with drug induced paralysis you couldn't just pull yourself out of it.

Answers and Replies

  • #3
Curare has no hypnotic effects so you're still awake after it paralyses you. It doesn't just paralyse the somatic nervous system though, it paralyses the autonomic nervous system so a high dose of it is fatal because it paralyses the muscles involved in breathing. I saw a documentary where they hooked a guy up to a respirator and injected him with curare and he says he was fully conscious and lucid throughout the whole thing. He could feel physical sensations too. I believe that curare antagonises ACh receptors at the neuromuscular junction, thats why it induces paralysis. Tetrodotoxin on the other hand blocks voltage gated sodium channels and I know that it causes paralysis (which is usually fatal since its so potent) but I don't know whether you can feel physical sensations, in other words I don't know whether it blocks efferent neural pathways. Theoretically, I assume it does because unlike ACh antagonism, blocking sodium channels should make it impossible for action potentials to be propagated, regardless of the direction.

I don't know what kind of anesthetics modern hospitals use but I know about the earlier ones such as chloroform, ether, halothane, nitrous oxide etc. Nitrous acts on multiple receptors and has a pretty complex mechanism but chloroform, ether, halothane etc. I believe bind to the benzodiazepine site on the GABA_a receptor. I don't know why these classes of drugs induce sleep (curare doesn't, not sure about tetrodotoxin) but I believe their sedative/anaesthetic properties are due to the influx of chloride ions which make cells much harder to depolarise. Do GABA modulators induce paralysis at high doses?
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