1. Nerve Agents

2. G-Series
First groups of nerve agents, the G-series, developed in Germany in 1936 by Dr. Schrader
Schrader’s group working to develop new insecticides for IG Farben
Developed the nerve agent Tabun; 5 ppm killed all insects dosed (1 ppm = 1 mg/L)
Schrader and coworker exposed when a drop of Tabun spilled on lab bench. Within minutes, they experienced miosis, dizziness, shortness of breath. Recovery took 3 weeks.
In 1935, Nazi government law required all inventions of military significance to be reported to Military of War; Tabun given code name Le-100 and Trilon-83

3. G-Series Schrader’s group discovered Sarin in 1938
Given code name T-144 or Trilon-46
Sarin was 10x more potent than Tabun
Soman discovered in 1944 by Dr. Kuhn in 1944
Cyclosarin discovered during WWII.
The G-series name created by United States when it uncovered the German research, labeling Tabun as GA (German Agent A), Sarin as GB, Soman as GD, Ethyl sarin as GE, and cyclosarin called GF.

4. Ct = product of concentration (C) of a vapor or aerosol to which one is exposed and the time (t) over which one is exposed to the concentration (C).
LCt50 = the Ct of an agent that will be lethal (L) to half of the population exposed to it
ICt50 = the Ct that will incapacitate (I) half of the population exposed to it
MCt50 = estimated Ct that will cause miosis (pinpointing of the pupils)

5. The LD50 of VX, when placed on human skin, is the size of a droplet that will cover the width of 2 columns of the Lincoln Memorial on a Lincoln penny.

6. Mechanism of Action Blocks acetylcholinestarase (AChE)
AChE is found in many different types of conducting tissue: nerve and muscle, central and peripheral tissues, motor and sensory fibers, and cholinergic and noncholinergic fibers; also found on red blood cell membranes
Normal function of AChE is to break down acetylcholine, which is a neurotransmitter in the nervous system. Under normal conditions, when the signaled action at each step is completed, acetylcholine is broken down by AChE, stopping the action.
If AChE is inhibited, acetylcholine continues to accumulate, and the nerves continue to send signals, or continue to fire. As the nerve continues to fire, the muscles and organs become hyperactive and twitch uncontrollably, and glands secrete copiously

7. Organophosphates &
Carbamates
- excess acetylcholine

8. The parts of the body affected by excessive acetylcholine accumulation:
Eyes
Nose (glands)
Mouth (glands)
Respiratory tract
Gastrointestinal tract
Cardiac muscle
Sweat glands
Skeletal muscle
Central nervous system

9. Eyes
Affected by direct contact with nerve agent; if route is through skin or ingestion, effect on eyes is delayed or may not occur
Main effect: miosis, or pinpointing, of the pupils
One or both pupils my be pinpointed and unresponsive to light or dark
Miosis causes a complaint of dim vision that is more pronounced in dim conditions
Frontal headache, mild aching around eye, or severe pains are common complaints of people exposed to moderate amounts
Twitching of eyelids may occur, eyes may be reddened

10. Nose Secretory glands of nose and mouth are senstive
When poisoning occurs dermally or by ingestion, nose will be affected, but only in response to systemic (whole body) involvement.
Nose will begin to run; “like a leaky faucet”
Mouth will secrete such excessive amounts of saliva that watery secretions run out the corners of the mouth

11. Respiratory tract
Inhalation of small amount will cause person to complain of tightness in the chest or shortness of breath (dyspnea);
This occurs because acetylcholine simulates the muscle in the airways to contract and constrict the airways (bronchoconstriction)
As concentration increases, breathing difficulty will become more severe
One or two breaths of high concentration will cause gasping and irregular respiration within seconds to a minute or two
Cessation of breathing can occur within minutes after exposure to large amount of vapor
Excessive bronchial secretions caused by stimulation of airway glands make breathing difficulties worse

12. Gastrointestinal (GI) tract
After exposure to large but sublethal exposure, person will complain of nausea and may vomit
Nausea and vomiting by be first effects from liquid nerve agent on skin
Person may belch and have diarrhea or involuntary defecation and urinaiton
Usually occur within several minutes of vapor exposure
After dermal exposure to liquid, the effects may not begin for as long as 18 hours after exposure

13. Cardiac Sweat glands Heart rate my increase or decrease after exposure
Blood pressure usually increases
Sweat glands
When skin penetration occurs after liquid or vapor exposure, localized sweating occurs and progressively spreads over the surrounding skin area

14. Skeletal muscles
After exposure to moderate or large amount or nerve agent, person will complain of weakness and twitching of muscle groups
Twitching can first be noticed at the site of the liquid drop on skin
Muscles may shoe a rippling effect (fasciculations)
As effects progress, muscles can go into prolonged contractions; large muscle groups may begin unsynchronized contractions that cause arms and legs to flail about; hyperactivity of muscles may lead to muscle fatigue and flaccid paralysis (limp, unable to move)

15. Central nervous system (CNS)
When large inhalation doses or liquid exposures occur, effects are rapid and usually fatal.
Person almost immediately loses consciousness, followed by seizures
Several minutes later, respiration ceases