A neurotoxin is any naturally-occurring or manmade compound that severely damages nerve tissues.
Neurotoxins cause damage, impairment, and total or partial destruction of the central nervous system. Neurotoxins can also create hormonal imbalances. Natural neurotoxins are usually found in animal venom or plants. Manmade neurotoxins are found in pesticides, drugs such as heroin and cocaine, and so on.
There are tons of neurotoxins—over 1,000 of them. Neurotoxins make their way into the human system either through ingestion, absorption through the skin, inhalation, or injection. While certain neurotoxic compounds only require a small amount to become toxic, others have to be taken in copious amounts.
A neurotoxin's effect on the central nervous system depends on various factors, including how toxic the substance is, as well as the age of the person and their health. Young and elderly people are more susceptible to the harmful effects of neurotoxins. Additionally, the length of exposure to the neurotoxin will have far-reaching effects on the central nervous system.
Example of Neurotoxins
The most common neurotoxin, believe it or not, is alcohol. You can find alcohol in alcoholic beverages such as wines, spirits, and beer and in trace amounts of medication such as cough syrups. When you ingest alcohol, its toxic nature's first and most obvious effect is impaired judgment and slowed reflexes. Most warning labels on alcohol bottles discourage you from using heavy machinery or driving while intoxicated (notice the word "toxic").
When you are exposed to alcohol over a longer period of time, the effects are more permanent and damaging. It greatly impairs your memory and cognitive abilities, sometimes irreversibly. If a pregnant woman drinks alcohol, the effects on the fetus are characterized by developmental delays in children and even brain damage.
Neurotoxins can also be found in some substances that are useful to the body. For instance, Vitamin A is vital for a healthy diet, but too much of it becomes toxic. The same with Vitamin B16. Some neurotoxic chemicals can be useful for medical procedures. Botulinum toxin is toxic to the human body in this form, but as Botox, doctors have used it for various cosmetic and medicinal purposes.
Types of Neurotoxins
As mentioned before, there are several neurotoxins in the world. Some of these occur in nature, like snake venom. This neurotoxin is introduced into the bloodstream via a snake bite. Most snake venom has the neurotoxic ability to prevent blood from clotting, paralysis, and widespread inflammation. This generally affects the central nervous system. If a doctor doesn't give you an antivenin, the toxicity leads to death.
Mercury is a metal and is extremely toxic if you ingest it—you can find trace amounts in tuna. Mercury can also be a fatal gas. Once ingested, this neurotoxin produces changes in the central nervous system, which lead to extreme fatigue, hearing loss, hallucinations, and death.
Some neurotoxins are manmade. During World War I, soldiers were exposed to neurotoxins as a result of chemical warfare. One of these nerve agents was Sarin. One drop of Sarin can have fatal consequences. Dioxins are another example of manmade neurotoxins. Dioxins are neurotoxic gases released into the atmosphere from combustion. This could be combustion from factories, burning fuels such as coal and firewood, and incineration of waste such as medical supplies. Dioxins harm a human's immune system. Cancers are an effect of dioxins on the human body.