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Dublin: 5 °C Tuesday 10 December, 2019

Column: 'Chemical weapons' are in the news for dreadful reasons – but what are they?

The images coming from Syria of small bodies wrapped in shrouds do not indicate the horrors of the moments before death – and the fact that humans are willing to inflict this on others must not be shied away from, writes Ann Cronin.

Ann Cronin

CHEMICAL WEAPONS ARE in the news again with dreadful consequences. While the international community dithers, the people of Syria must await investigations into how – rather than why – so many civilians are dying before aid is extended.

While all methods of killing are abhorrent, chemical weapons are particularly vile; but the end result of any attack on people is the same. Being shot or killed by shrapnel or poisoned all result in death but for the UN a chemical attack represents a strange line that cannot be crossed.

Rooted in the horror of mustard gas in trenches of WWI, chemical weapons are but another means to kill; but in 1993, the United Nations Chemical Weapons Convention was signed by 162 members prohibiting the stockpiling and manufacture of these weapons.

Sarin, tabun and mustard gas

Syria is one of the six non-signatories of the convention and is thought to be producing chemical weapons such as sarin, tabun and mustard gas. While the discussion of why one form of killing people is outlawed in comparison with another is a worthy subject, today I turn our attention to what exactly a chemical weapon does.

Chemical weapons can be classed according to effect:

  • Nerve agents such as sarin, cyclosarin and tabun
  • Blister agents like mustard gas or lewisite
  • Choking agents such as phosgene or chloropicrin

As this piece is primarily concerned with the recent events in Syria I will focus primarily on nerve agents. While evidence remains scant, the remains of the victims showed no sign of blistering so I exclude blister agents.

Exaggerated ‘natural’ responses

What a chemical can and does do is act on existing molecules in our body to produce an exaggerated ‘natural’ response. Bodies function and react through communication between cells. The messengers between these cells act to tell various parts of your musculature, your organs, and your brain to act in particular ways.

Acetylcholine is one of these messengers, and it has two main effects: on your skeleton, it tells muscles to contract and tighten and, inversely, it causes heart muscle to relax. Acetylcholine is the primary molecule released in parasympathetic activation. The parasympathetic system is the ‘rest and digest’ system, it slows down the heart, lowers blood pressure, increases gut movement – the exact opposite of the sympathetic system which prepares you for ‘fight or flight’.

Acetylcholine is released from one cell and signals a second cell, it is then broken down by enzymes called acetylcholinesterases. This is a necessary and natural part of how your body reduces waste and recycles products in order to maintain your system.

Clinical uses for chemicals exist

There are a number of clinical uses for chemicals which target and prevent acetylcholinesterase from working. The majority of these are short acting or reversible. Conditions such as Myasthenia Gravis or glaucoma are treated by giving drugs called acetylcholinesterase inhibitors. They inhibit the action of the drugs that break down acetylcholine, leading to more and more signalling between cells telling the relevant muscles to contract or relax.

Chemical weapons like Sarin are irreversible inhibitors of this enzyme, this leads to a build up of acetylcholine at the signalling point between cells. These repeated ‘messages’ to the body mean that muscles contract more or less depending on the site of action. Firstly there is contraction of all the bodily muscles, leading to spasm and voiding of the bowels and urination. The lungs tighten but also produce a massive amount of saliva and mucus.

As it slows down the heart by inhibiting cardiac muscle, so heart rate drops. The pupil contracts and tears up, vision blurs and the nose runs. This occurs within seconds of exposure, and death can result between one and 10 minutes after exposure. Treatment for those lucky enough to reach help is usually with Atropine but this is dependent on dose and exposure.

We can’t ignore the realities of what is happening

Sarin is not just inhaled through the lungs, it can permeate clothing and skin. It also permeates the environment and can affect people who come in contact with exposed patients. In its liquid form it can be used to poison food or water supplies, its effects dependent on the level of exposure and individual variants. Children are at increased risk from nerve agents at lower doses, reasons why pesticides and insecticides (who work on the same system but at safe levels) should be kept out of reach.

The images coming from Syria of small bodies wrapped in shrouds do not indicate the horrors of the moments before death, perhaps the stilled and outwardly flawless faces hide that too well. While the death of any civilian in any conflict is unconscionable, whether they die through conventional or chemical means, that man is willing to inflict this on another must not be looked away from.

Silent sleeping children are merely fairy tale from the nightmare that these people must be living.

Ann Cronin is a neuropsychopharmacologist and writes about psychology, mental health and drug effects, her research interests include Group Action, Art and Memory. She blogs at Brains NOT Shoes.

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Ann Cronin

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