Your body produces its own acetylcholine, in part using choline the body gets from foods you eat. Egg yolks, legumes, and seeds are some of the foods that are rich in choline. While scientists know a lot about how acetylcholine affects the movement of your skeletal muscles, the neurotransmitter’s role in the brain and central nervous system is not as well understood. [3] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
To better understand how this works, consider what happens when you pick up an object. Think of all the tiny muscles in your hand that have to move for you to grasp the object and hold it firmly. Acetylcholine sent the message that triggered each of those muscles to contract. When you’re bitten by a black widow spider, the venom stimulates a flood of acetylcholine that causes excessive muscle contractions. Eventually, all of your acetylcholine will be released, resulting in paralysis. [5] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
In your cardiovascular system, acetylcholine decreases your heart rate, and reduces the force of cardiac muscle contractions. It also dilates your blood vessels to lower your blood pressure. In your lungs, acetylcholine helps you breathe more deeply and take more air into your lungs. In your eyes, acetylcholine causes your pupils to dilate in response to light and helps you focus. These contractions also stimulate secretions, so you can thank acetylcholine every time you sweat or salivate. In the male reproductive system, acetylcholine is also responsible for erections.
A sensory gating deficit is an important symptom of many mental disorders, including bipolar disorder, post-traumatic stress disorder (PTSD), and schizophrenia. People with traumatic brain injury (TBI) and epilepsy also have a high likelihood of experiencing a sensory gating deficit.
Acetylcholine also plays a role in helping you maintain attention and focus while completing tasks, which enables you to learn new things.
One of the side effects of drugs that inhibit acetylcholine is short- and long-term memory loss.
There has also been some evidence that anticholinergic drugs (drugs that reduce acetylcholine levels) ease depressive symptoms in people with major depressive disorder and bipolar disorder.
Those receptors do respond to nicotine (they’re technically called “nicotinic receptors”), and nicotine provides short-term relief from sensory gating and executive functioning deficits. This relationship could explain the relatively high levels of cigarette smoking among adults with ADHD. Medication that targets acetylcholine receptors is especially effective for adults with ADHD.
Stimulating acetylcholine receptors can also improve executive functioning, planning, and organization problems.
An acetylcholine deficiency in the brain can also cause delusions and confusion, both of which often occur in people with Alzheimer’s disease or dementia.
Studies have shown that stimulation of acetylcholine receptors improves motor control symptoms of patients with Parkinson’s disease, but there is still more research to be done to understand how the dopamine and acetylcholine systems work together.
Because acetylcholine stimulates movement in these muscles, increasing overall acetylcholine levels helps people with this disease regain control of their muscles and increase their muscle strength.
People with LEMS experience weakness in their muscles because of the decreased muscle contractions. The upper legs and hips are typically the most affected, which leads to difficulty walking. Weakness in the upper arms and shoulders can also occur and makes self-care difficult.
Nicotine mimics acetylcholine and triggers the same receptors as the neurotransmitter. Researchers speculate that this accounts for the higher level of smoking among people with schizophrenia—80% of individuals diagnosed with schizophrenia smoke up to 30 cigarettes a day, which is likely a method of self-medication. [18] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
A study published in 2022 was the first to include OTC antihistamines, such as Benadryl, and confirm that they carry this risk as well. The risk is especially high for older adults since acetylcholine production diminishes as you age. Not surprisingly, short-term side effects of antihistamines include confusion, drowsiness, dry mouth, urine retention, constipation, and problems with short-term memory. These are all functions acetylcholine helps control.
Tricyclic antidepressants, such as amoxapine and doxepin, were the first commercially available antidepressants. Side effects of these medications related to acetylcholine include dry mouth, constipation, urine retention, drowsiness, and blurred vision. Because there are newer antidepressants on the market with fewer side effects, tricyclics are seldom prescribed.
Common cholinergic medications include galantamine (Reminyl) and donepezil (Aricept). Side effects include sleep disturbance, agitation, and gastrointestinal issues.
Examples of anticholinergic medications include scopolamine, which is used to prevent nausea and vomiting, and diphenhydramine, which is used as a sleeping aid. Botulinum toxin (BOTOX) also prevents the release of acetylcholine, which in turn prevents movement. This is why it’s injected to help prevent and reduce the appearance of facial wrinkles. [24] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source Side effects of these medications include reduced saliva and tear production, constipation, urinary retention, blurred vision, flushing, and diminished muscle contraction.
Researchers are studying the potential for these drugs to improve cognitive function for people with schizophrenia, bipolar disorder, major depressive disorder, and other mental disorders that affect executive functioning. Common acetylcholinesterase inhibitors include donepezil (Aricept) and galantamine (Reminyl). Increased sweat, saliva, and tears may occur with acetylcholinesterase inhibitors. Other side effects include slow heart rate, constriction of the airways, and constriction of the pupils in the eyes.
If you don’t like coffee or tea, you can also take a caffeine supplement. Capsules are available online and in most brick-and-mortar stores where nutritional supplements are sold.
As a rule of thumb, foods that are high in fat and cholesterol tend to have a lot of choline. [36] X Research source
If you take a choline supplement, limit your total intake to no more than 3g a day, including choline from other sources. More than that could result in high blood pressure and increase your risk of heart disease.
Gingko biloba[39] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source Huperzine A[40] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source Bacopa monnieri[41] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source Ginseng[42] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
Blurry vision Nausea, vomiting, and diarrhea Wheezing and shortness of breath Increased sweating and salivating Frequent and more urgent urination Slow heart rate (fewer than 60 beats per minute) Paralysis[44] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source
