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Author Topic: Nerve Agents  (Read 7857 times)

Offline dont_panic

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Nerve Agents
« on: 09/12/2005 21:00:09 »
How do nerve agents actually work? Presumably attacking the nervous system; but after doing research on the internet all i seem to come up with is how the Nazi's used them. Its terribly frustrating. Hope you lot can help, Thank you all.


 

another_someone

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Re: Nerve Agents
« Reply #1 on: 09/12/2005 22:20:03 »
quote:
Originally posted by dont_panic

How do nerve agents actually work? Presumably attacking the nervous system; but after doing research on the internet all i seem to come up with is how the Nazi's used them. Its terribly frustrating. Hope you lot can help, Thank you all.



Nerve agents are a type of organophosphate (they are very similar to some insecticides, such as DDT the theory being that a mild organophosphate can cause havoc with an insect while only having a minimal impact on larger animals such as humans).

http://pmep.cce.cornell.edu/profiles/extoxnet/TIB/cholinesterase.html
quote:

WHAT IS CHOLINESTERASE?
Cholinesterase (ko-li-nes-ter-ace) is one of many important enzymes needed for the proper functioning of the nervous systems of humans, other vertebrates, and insects. Certain chemical classes of pesticides, such as organophosphates (OPs) and carbamates (CMs) work against undesirable bugs by interfering with, or 'inhibiting' cholinesterase. While the effects of cholinesterase inhibiting products are intended for insect pests, these chemicals can also be poisonous, or toxic, to humans in some situations.
Human exposure to cholinesterase inhibiting chemicals can result from inhalation, ingestion, or eye or skin contact during the manufacture, mixing, or applications of these pesticides.
HOW DOES IT WORK?
Electrical switching centers, called 'synapses' are found throughout the nervous systems of humans, other vertebrates, and insects. Muscles, glands, and nerve fibers called 'neurons' are stimulated or inhibited by the constant firing of signals across these synapses. Stimulating signals are usually carried by a chemical called 'acetylcholine' (a-see-till-ko-leen). Stimulating signals are discontinued by a specific type of cholinesterase enzyme, acetylcholinesterase, which breaks down the acetylcholine. These important chemical reactions are usually going on all the time at a very fast rate, with acetylcholine causing stimulation and acetylcholinesterase ending the signal. If cholinesterase-affecting insecticides are present in the synapses, however, this situation is thrown out of balance. The presence of cholinesterase inhibiting chemicals prevents the breakdown of acetylcholine. Acetylcholine can then build up, causing a "jam" in the nervous system. Thus, when a person receives to great an exposure to cholinesterase inhibiting compounds, the body is unable to break down the acetylcholine.
Let us look at a typical synapse in the body's nervous system, in which a muscle is being directed by a nerve to move. An electrical signal, or nerve impulse, is conducted by acetylcholine across the junction between the nerve and the muscle (the synapse) stimulating the muscle to move. Normally, after the appropriate response is accomplished, cholinesterase is released which breaks down the acetylcholine terminating the stimulation of the muscle. The enzyme acetylcholine accomplishes this by chemically breaking the compound into other compounds and removing them from the nerve junction. If acetylcholinesterase is unable to breakdown or remove acetylcholine, the muscle can continue to move uncontrollably.



The uncontrolled muscle spasms caused by nerve agents means that you lose control of much of your body, including your bowels, bladder, and respiration; ultimately causing asphyxiation.  It may also have some effect upon your brain (there have been stories about some insecticides causing raised levels of aggression).
 

Offline dont_panic

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Re: Nerve Agents
« Reply #2 on: 10/12/2005 16:49:04 »
ahh much better...i feel the urge for learning about this subject fading ^_^. i will have a closer look at that website another time though. Thanks you lots.
 

Offline padfoot89

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Re: Nerve Agents
« Reply #3 on: 11/12/2005 10:39:55 »
Nerve agents are also found in nature.
Certain snakes' poison also contain nerve agents.It kills by affecting the nervous system.
HISS

lobo
 

another_someone

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Re: Nerve Agents
« Reply #4 on: 11/12/2005 13:39:57 »
quote:
Originally posted by padfoot89

Nerve agents are also found in nature.
Certain snakes' poison also contain nerve agents.It kills by affecting the nervous system.
HISS

lobo



As I understand it, snake venom has pretty much the opposite effect.

Organophosphates  block the effects of cholinesterase, which cause a build up of acetylcholine, which then causes muscle spasms.

Snake venom blocks the effects of  acetylcholine, which causes paralyses (snakes do not wants their meal having muscle spasms as they are trying to swallow it).  This effect is also used in pre-med injections as a muscle relaxant to effectively paralyse a patient  before the go under surgery (so that they do not start involuntarily moving around on the operating table).

Another component of snake venom includes various digestive juices.  Since a snake cannot chew its food, but swallows it whole, it starts its digestion of its meal (from the inside out) even before it has swallowed it.
 

Offline dont_panic

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Re: Nerve Agents
« Reply #5 on: 17/12/2005 20:34:15 »
Would it be possible to make a nerve agent that mearly stunning the nervous system, rendering the person paralysed for a while, but they could then recover either with time or an antidote?
 

another_someone

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Re: Nerve Agents
« Reply #6 on: 18/12/2005 00:31:11 »
quote:
Originally posted by dont_panic

Would it be possible to make a nerve agent that mearly stunning the nervous system, rendering the person paralysed for a while, but they could then recover either with time or an antidote?



I would think that nerve agents have too broad a spectrum of effects (everywhere there are nerves) to be able to fine tune in that way.

The Russians did try and use opiate derivatives in that way to end siege of the Moscow theatre in 2002.  They killed 117 (some reports say 130) of the hostages (as well as most of the hostage takers although it seems most of those were shot in the head while unconscious), but saved 650 of the hostages.  Had they let the medical staff know what the gas was they had used, rather than classifying it as a military secret, it may well have been that more of hostages could have been saved.
 

Offline dont_panic

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Re: Nerve Agents
« Reply #7 on: 18/12/2005 19:33:52 »
Did the Russian public know they were planning on using nerve agents?
 

another_someone

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Re: Nerve Agents
« Reply #8 on: 19/12/2005 01:00:32 »
quote:
Originally posted by dont_panic

Did the Russian public know they were planning on using nerve agents?



I'm sorry, I think there must have been a misunderstanding; opiates are not nerve agents, they are drugs related to heroin and morphine (the actual chemical is suspected to be a Fentanyl derivative; but, to this day, the Russians have refused to actually make public what the chemical was).

The Russian public would not have known anything in advance, but that is understandable since the special forces had to maintain the element of surprise, and publicising the means of rescue would not be consistent with maintaining that surprise.  The valid criticism of the Russian administration was their reluctance to release information after the operation was over, information that could have helped to save many of the hostages lives.

One political question that did arise was whether the Russians were in violation of the treaty banning the development and use of chemical weapons for military purposes.  Although this was only intended to be an incapacitating agent (albeit, it also proved itself very toxic), but it is still technically a chemical weapon.
 

Offline muse

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Re: Nerve Agents
« Reply #9 on: 23/01/2006 19:17:23 »
quote:
Originally posted by dont_panic

How do nerve agents actually work? Presumably attacking the nervous system; but after doing research on the internet all i seem to come up with is how the Nazi's used them. Its terribly frustrating. Hope you lot can help, Thank you all.



Nerve agents are organophosphates or carbamates. The most known agent are probably sarin, soman and VX (chemical warfare agents) and parathion and malathion (insecticides). Most of the chemicals are extremly poisonous. You will find some information here:
newbielink:http://www.mitretek.org/BackgroundOnChemicalWarfare.htm [nonactive]

They work by binding to the enzyme acetylcholine esterase (AChE), inhibiting the enzyme. When this happends the enzyme is not able to break down the neurotransmitter acetylcholine (ACh) in the synapses. To much ACh in the synapses will trigger the neuroreseptor repeatedly, and you will have spasm etc.

There are different types of antidote to administer after being poisoned with nerveagents. The three primary treatments is to 1) reduce spasm and 2) breaking the bond between nerveagent and enzyme 3)anticonvulsants.
To reduce spasm you administer ex atropine which binds to the reseptors in the synapses and there by blocking ACh from trigger the muscle. To break the bond you need reactive molecules like oximes. (ex pralidoxime) These molecules will break the bond between nerve agent and enzym, and this activates the enzyme again. Anticonvulsants such as diazepam (Valium) are given to prevent convulsion.

Oximes has to be given shortly after poisoning to hinder aging of the enzyme-nerveagent complex. Aging happends when the nerve agent binds irreversibly to the enzyme.

It's a lot of information about this subject on internet. Try search for ex chemical warfare agents, acetylcholin esterase, sarin, soman etc. Wikipedia also have a lot of information.
newbielink:http://en.wikipedia.org/wiki/Nerve_agent [nonactive]

Muse
 

Offline Soul Surfer

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Re: Nerve Agents
« Reply #10 on: 25/01/2006 20:04:54 »
Muse are you by any remote chance a surfer from belgium?

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Offline muse

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Re: Nerve Agents
« Reply #11 on: 02/02/2006 21:20:55 »
quote:
Originally posted by Soul Surfer

Muse are you by any remote chance a surfer from belgium?




Nope. From Norway.
 

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Re: Nerve Agents
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