Nerve agent

Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter. Nerve agents are irreversible acetylcholinesterase inhibitors used as poison. Poisoning by a nerve agent leads to constriction of pupils, profuse salivation, convulsions, and involuntary urination and defecation, with the first symptoms appearing in seconds after exposure. Death by asphyxiation or cardiac arrest may follow in minutes due to the loss of the body's control over respiratory and other muscles. Standard treatment for nerve agent poisoning is a combination of an anticholinergic to manage the symptoms, and an oxime as an antidote. The most mass-produced nerve agents in history are VX/VR, sarin, and soman. The G-series consists of the earliest nerve agents discovered from the late 1930s, which are typically volatile and dangerous via inhalation as aerosols. The V-series, discovered after the 1950s, are far less volatile and more persistent, and threaten via skin absorption, requiring a full body suit. Both series, and some Novichok-series compounds, are organophosphate compounds, while other Novichok agents, and some carbamate nerve agents, have non-organophosphate chemistry. Some are formed by binary chemical weapon munitions, such as the US M687 artillery shell which formed sarin by mixing its chemical precursors. The first nerve agents were discovered by IG Farben in Nazi Germany. The extreme toxicity of tabun was learned in 1936, followed by sarin in 1938 and soman in 1944. The Wehrmacht became the first military to stockpile nerve agent munitions, but they were not used for fear of Allied retaliation. France, the Soviet Union, the United Kingdom, and the United States all captured and studied German nerve munitions. During the Cold War, the Soviet and United States chemical weapons program became the first and second largest in history, primarily stockpiling thousands of tons nerve agents alongside mustard gas. Ba'athist Iraq also developed nerve agents, becoming the first country to use them in warfare, killing tens of thousands of civilians and troops in the Iran–Iraq War. This began with a tabun attack in 1984 and included the Halabja massacre, which killed over 3,000 people. The Japanese doomsday cult Aum Shinrikyo was the first to use nerve agents for chemical terrorism, killing dozens in the 1994 Matsumoto sarin attack, 1995 Tokyo subway sarin attack, and assassination attempts with VX-filled syringes. Ba'athist Syria's also used sarin in the Syrian civil war, including the 2013 Ghouta attack, which killed between three hundred and seventeen hundred people. Nerve agent development, production, and stockpiling were first comprehensively banned by the 1993 Chemical Weapons Convention, adopted by 193 states as of 2026. Despite this, nerve agents were used in the assassination of Kim Jong-nam and poisoning of Sergei and Yulia Skripal, allegedly ordered by North Korea and Russia respectively. Nerve agents are generally colorless liquids under normal conditions; the popular term "nerve gas" is inaccurate. Agents sarin and VX are odorless; tabun has a slightly fruity odor and soman has a slight camphor odor.

Biological effects Nerve agents attack the nervous system. All such agents function the same way resulting in cholinergic crisis: they inhibit the enzyme acetylcholinesterase, which is responsible for the breakdown of acetylcholine (ACh) in the synapses between nerves that control whether muscle tissues are to relax or contract. If the agent cannot be broken down, muscles are prevented from receiving 'relax' signals and they are effectively paralyzed. It is the compounding of this paralysis throughout the body that quickly leads to more severe complications, including the heart and the muscles used for breathing. Because of this, the first symptoms usually appear within 30 seconds of exposure and death can occur via asphyxiation or cardiac arrest in a few minutes, depending upon the dose received and the agent used. Initial symptoms following exposure to nerve agents (like Sarin) are a runny nose, tightness in the chest, and constriction of the pupils. Soon after, the victim will have difficulty breathing and will experience nausea and salivation. As the victim continues to lose control of bodily functions, involuntary salivation, lacrimation, urination, defecation, gastrointestinal pain and vomiting will be experienced. Blisters and burning of the eyes and/or lungs may also occur. This phase is followed by initially myoclonic jerks (muscle jerks) followed by status epilepticus–type epileptic seizure. Death then comes via complete respiratory depression, most likely via the excessive peripheral activity at the neuromuscular junction of the diaphragm. The effects of nerve agents are long lasting and increase with continued exposure. Survivors of nerve agent poisoning almost invariably develop chronic neurological damage and related psychiatric effects. Possible effects that can last at least up to two–three years after exposure include blurred vision, tiredness, declined memory, hoarse voice, palpitations, sleeplessness, shoulder stiffness and eye strain.

… excerpt ends here. Continue reading the full article.