Acetylcholine - what is it?

Acetylcholine (ACh) is an abundant neurotransmitter in the human body. It occurs in both the central nervous system (CNS) and peripheral nervous system (PNS).    The name acetylcholine comes from its structure - it is a chemical compound consisting of acetic acid and choline. Acetylcholine has a number of functions, many of which may be impaired by diseases or medications that affect the function of this neurotransmitter.

Acetylcholine can be found in all motor neurons, where it stimulates muscles to contract. From the movements of the stomach and heart to the blink of an eye, all body movements are related to the action of this important neurotransmitter, which is found in many neurons in the brain and plays an important role in mental processes such as memory and cognition.

DISCOVERY

Acetylcholine was the first identified neurotransmitter, discovered by Henry Hallett Dale in 1914, and its existence was later confirmed by Otto Loewi. Both people received the Nobel Prize in 1936 for their discovery.

ACETYLCHOLINE IN THE CENTRAL NERVOUS SYSTEM AND PERIPHERAL NERVOUS SYSTEM

Acetylcholine in the body affects, among others:

In the PNS, acetylcholine is a major part of the somatic nervous system. In this system, it plays a stimulating role, leading to voluntary muscle activation. In the autonomic system, acetylcholine controls a number of functions, acting on neurons in the sympathetic and parasympathetic systems. It also participates in the contraction of smooth muscles and dilation of blood vessels, and may also contribute to slowing the heart rate. Since acetylcholine plays an important role in muscle function, drugs that affect this neurotransmitter can cause varying degrees of movement disruption and even paralysis.

Acetylcholine also acts in various places in the CNS, where it can act as a neurotransmitter and neuromodulator. It plays a role in motivation, arousal, attention, learning and memory, and is also involved in promoting REM sleep. 

Disturbed acetylcholine levels may be associated with Alzheimer's disease. Drugs and substances that interfere with the action of acetylcholine can have a negative effect on the body and even lead to death. Examples of such substances are certain types of pesticides and nerve gases. 

Black widow spider venom also interacts with acetylcholine, i.e. when a person is bitten by a black widow, their acetylcholine levels increase dramatically, leading to severe muscle spasms, paralysis, and it can even lead to death.

ACETYLCHOLINE AND ALZHEIMER'S DISEASE

According to the National Institute on Aging, Alzheimer's disease is the most common cause of dementia among older people. Its symptoms include severe memory loss and problems with thinking, disrupting daily life. Unfortunately, there is currently no cure for Alzheimer's disease. Experts don't know what causes Alzheimer's disease. However, they know that many people with this disease have lower levels of acetylcholine. Alzheimer's disease damages the cells that produce and use acetylcholine. Some medications can increase acetylcholine levels by blocking the action of enzymes that break down the neurotransmitter.

The basic enzyme in this group is acetylcholinesterase (AChE), and drugs that reduce the activity of these enzymes are called AChE inhibitors or cholinesterase inhibitors. AChE inhibitors can help with thought processes such as language, judgment and memory. 

AChE inhibitors include:

• donepezil (Aricept)
• galantamine (Razadyne)
• ryvastigmina (Exelon)

AChE inhibitors may also help treat other conditions. According to some studies, specific tumors appear to have unusual levels of AChE. Scientists indicate that AChE inhibitors may help treat some types of cancer.

ACETYLCHOLINE AND MYASTARDS GRAVIS

Myasthenia gravis is an autoimmune condition that causes muscle weakness, especially when a person is active. Myasthenia gravis causes the immune system to block or destroy acetylcholine receptors. Then the muscles do not receive the neurotransmitter and cannot function normally. In particular, without acetylcholine, muscles cannot contract. 

Symptoms of myasthenia gravis can range from mild to severe and may also include:

• weakness in the arms, legs, hands, fingers or neck
• dropping of one or both eyelids
• blurred or double vision
• trouble swallowing
• shortness of breath
• difficulty speaking

Many people with myasthenia gravis can lead normal lives. A variety of treatments can control symptoms. AChE inhibitors, which doctors prescribe to treat Alzheimer's disease, may also help alleviate the symptoms of myasthenia gravis. These drugs slow down the breakdown of acetylcholine, improve the neuromuscular connection and muscle strength.

ACETYLCHOLINE AND PARKINSON'S DISEASE

An imbalance in acetylcholine levels can also affect people with Parkinson's disease, as the body needs a balance of acetylcholine and dopamine, another chemical messenger, to control movements well. Parkinson's disease is a neurodegenerative condition that causes involuntary movements, tremors, and difficulties with thinking and mood.

The exact causes of Parkinson's disease are unknown. However, experts have found that people with this condition often have a drop in dopamine that allows acetylcholine to take over. When this happens, the muscles become over-excited, leading to symptoms such as jerking movements and tremors. For this reason, some Parkinson's disease medications block the effects of acetylcholine. This allows dopamine levels to be rebalanced, which may help alleviate some symptoms. These drugs are called anticholinergic drugs. They may also help relieve dyskinesia, which is excessive movement and can be a side effect of other Parkinson's medications.

Anticholinergics are not for everyone. Side effects may include confusion, memory loss, hallucinations and blurred vision. Experts also believe that many of the non-motor symptoms of Parkinson's disease, such as memory problems, are related to reduced acetylcholine levels.

TOXINS, PESTICIDES AND ACETYLCHOLINE

Exposure to organophosphate pesticides (OP) or certain warfare agents can cause very high increases in acetylcholine levels in the body. The Centers for Disease Control and Prevention (CDC) says these types of chemicals lead to the buildup of acetylcholine in the nervous system, causing symptoms such as:

• wheezing
• weakness
• headaches
• fainting,
• diarrhea and vomiting
• mental changes
• muscle twitching
• convulsions
• paralysis
• breathing hold

A person can be exposed to these chemicals through skin, breathing, or ingestion. In the United States, approximately 8,000 people are exposed to OPs annually. Exposure most often occurs through contact with pesticides on crops such as apples, grapes, spinach, cucumbers and potatoes.

CAN YOU INCREASE ACETYLCHOLINE LEVEL?

There is no proven way to increase acetylcholine levels. However, some evidence suggests that consuming choline, another nutrient, may help. The body needs choline for the proper functioning of the brain and nervous system. 

What are the other functions of acetylcholine? It is also necessary for muscle control and affects the formation of healthy membranes around the body's cells. Choline is also a building block of acetylcholine. It is accepted that people need to obtain enough choline from their diet to produce adequate levels of acetylcholine.

The Office of Dietary Supplements confirms that some animal studies have shown that higher choline intake may lead to better cognitive function. Additionally, choline intake during pregnancy and early development also improves cognitive function and helps prevent age-related memory decline.

It turns out that many food products contain choline, including:

• meat
• fish
• eggs
• beans
• cruciferous vegetables
• whole grain products
• dairy
• nuts
• seeding

Huge numbers of people don't get enough choline in their diet. The recommended amount is 425 milligrams per day for women and 550 milligrams for men. A person can take choline supplements, but high doses can cause side effects such as vomiting, fishy body odor, and liver damage. So let's remember that before using any supplement, it is worth consulting it with a doctor, pharmacist or dietitian. 

BOTOX AND ACETYLCHOLINE

Botulinum toxin, better known as Botox, can treat a variety of muscle-related conditions. Botox injections can also treat migraine headaches, excessive sweating, and some bladder and bowel problems. Additionally, Botox is the most popular non-surgical cosmetic treatment in the U.S. according to the American Society of Plastic Surgeons.

Botox works primarily by interfering with acetylcholine in the target muscle. For example, injecting Botox into certain facial muscles can temporarily reduce wrinkles because it prevents muscle spasms and makes the skin on top of the muscle appear smoother. For this reason, Botox and acetylcholine are often mentioned as related elements.