Neurotransmitters

Neurotransmitter Information


When stimulated in a manner that triggers them, neurons (nerve cells) release neurotransmitters. The neurotransmitters travel across a minute gap, called a synapse, to the neurotransmitter receptors on other nerve cells, gland cells, or muscle cells.

Neurotransmitters are involved in communication between different parts of the brain, and communication between the brain and the body. Among other functions, neurotransmitters play a prominent role in our thinking and movement.

In the early part of the 20th century, acetylcholine was the first neurotransmitter to be observed. Henry Hallett Dale identified it, and Otto Loewi confirmed it as a neurotransmitter. Dale and Loewi were awarded 1936 Nobel Prize in Physiology or Medicine for their work.

Acetylcholine
Dopamine
Endorphins
Epinephrine
GABA
Glutamate
Histamine
Norepinephrine
Oxytocin
Serotonin
Bio-Synthesis
Neurotransmitter Notes
Neurotransmitter Links


Acetylcholine

Acetylcholine Chemical Structure

Acetylcholine (abbreviation Ach) affects mental actions related to cognition (including thinking, learning, memory, understanding, etcetera). In addition, acetylcholine is released by motor neurons in the nervous system to trigger muscle actions.

An acetylcholine imbalance can cause problems that include:
--- Impaired Thinking.
--- Impaired Memory.
--- Difficulties With Movement.

For more information about the symptoms of reduced and excessive levels of acetylcholine, including methods of increasing or decreasing them, see the acetylcholine page on this site that is located here.


Dopamine

Dopamine Chemical Structure

Dopamine (abbreviation DA) affects mental processes related to mood, emotions, attention, focus, memory, drive, motivation. It also plays a part in the perception of pain. In addition, dopamine has an effect on our physical movement.

A dopamine imbalance can contribute to problems that include:
--- Impaired Thinking And Concentration.
--- Low Energy.
--- Pain.
--- Depression.
--- Reduced Social Interaction.

For more information about the symptoms of reduced and excessive levels of dopamine, including methods of increasing or decreasing them, see the dopamine page on this site that is located here.


Endorphins

Endorphins are a group of chemical compounds the body produces naturally in response to pain or physically strenuous activity. They reduce the amount of pain we feel and can also induce feelings of well being.

An endorphin imbalance can cause problems that include:
--- Chronic Pain (of unknown cause).
--- Reduced Pain Tolerance.
--- Chronic Fatigue.
--- Depression.

For more information about the symptoms of reduced levels of endorphins, including methods of increasing them, see the page about endorphins on this site that is located here.


Epinephrine (Adrenalin, Adrenaline)

Epinephrine, aka adrenalin or adrenaline (abbreviation Epi or Ad), is related to the neurotransmitter norepinephrine. Their chemical structures are similar, but epinephrine has an additional methyl group where noradrenaline has a hydrogen atom.

In stressful situations, the human body releases more epinephrine, noradrenaline, other chemicals. Elevated levels of these chemicals has a major effect on the fight or flight response, which gets the body ready to fight or run from a possibly dangerous situation.

In humans, epinephrine is synthesized in the adrenal glands and by certain nerve cells (neurons). Excessive levels of epinephrine and/or norepinephrine can cause:
--- Stress Related Responses.
--- Sweating.
--- Shaking.


GABA (Gamma-Aminobutyric Acid)

GABA Chemical Structure

Normal levels of GABA have a calming effect that reduces anxiety and excitability in humans and other mammals. GABA also affects attention, emotions, vision, motor control, muscle tone, pain perception.

Low levels of GABA can contribute to anxiety, hypertension, insomnia, mania. reduced impulse control. High levels of GABA can contribute to apathy, impaired memory, reduced inhibition, reduced motivation, excessive daytime sleepiness.

For more information about the symptoms of reduced and excessive levels of GABA, including methods of increasing or decreasing them, see the GABA page on this site located here.


Glutamate

Glutamate (abbreviation Glu) is associated with brain development, learning, memory, language, speech, maintaining nerves in the brain. Glutamate binds to AMPA receptors, NMDA receptors, metabotropic glutamate receptors, kainate receptors.

Glutamate is linked to illnesses such as autism, migraines, Alzheimer's Disease, Amyotrophic Lateral Sclerosis (ALS), Huntington's Disease, obsessive-compulsive disorder (OCD), Parkinson's Disease, schizophrenia. Glutamate is a precursor to GABA.

A glutamate imbalance can be hard to diagnose because the most common symptoms are also present in many other types of health problems. If you think you may be suffering a glutamate imbalance talk to your doctor before trying to balance glutamate levels yourself.


Histamine

Histamine (abbreviation H) is involved in many mental and physical functions. It affects allergies, cognition, hives, inflammation, vasodilation, blood pressure, body temperature, sexual libido, perception of itchiness, stable equilibrium related to glands.

Other things it impacts include:
--- Sleep-wake cycle.
--- Mucous membrane of nose.
--- Appetite, digestion, stomach function.
--- Bronchial smooth muscle contraction.
--- Sensory nervous system response to harmful stimuli.

A build up of histamine in the body can result in a problem called histamine intolerance. Symptoms include diarrhea, headaches, migraines, eczema, hives, rashes, congestion, itchy eyes, runny nose, low blood pressure, premenstrual cramping or headaches.


Norepinephrine (Noradrenalin, Noradrenaline)

Norepinephrine, also called noradrenalin or noradrenaline (abbreviation NE or NAd), is closely related epinephrine. The structure of both are similar, but epinephrine has an additional methyl group where noradrenaline has a hydrogen atom.

Norepinephrine impacts some mental processes that epinephrine does not. Low levels can contribute to depression, reduced energy, impaired thinking. Excess levels can contribute to anxiety disorders, hyperactivity, mania, related conditions.

For more information about the symptoms of reduced and excessive levels of norepinephrine, including methods of decreasing them, see the norepinephrine page on this site that is located here.


Oxytocin

Oxytocin (abbreviation OT) is associated with love, bonding, feelings of well being. While it is usually thought of as a positive neurotransmitter, it has been shown to increase social emotions in general. Not just positive, but negative emotions too.

This seems to be related to how we feel about the person or persons we are socially involved with. An increase in oxytocin with people we like tends to increase the level of positive emotions involved.

But when we are socially interacting with people we do not like (or who we feel are adversaries at that particular time) an increase in oxytocin can result in heightened negative emotions towards those we regard as opponents.


Serotonin

Serotonin Chemical Structure

Serotonin (abbreviation 5-HT) is a neurotransmitter most commonly associated with mental health. It affects mood, learning, memory, sleep. The majority of serotonin in our body is in the gastrointestinal tract where it affects digestion and appetite.

A serotonin imbalance can contribute to problems that include:
--- Depression.
--- Mood Swings.
--- Problems With Digestion.

For more information about the symptoms of reduced and excessive levels of serotonin, including methods of increasing them, see the serotonin page on this site that is located here.


Bio-Synthesis Of Selected Neurotransmitters

Some of the more important vitamins and minerals that are necessary for the proper bio-synthesis of neurotransmitters include:

--- Magnesium.
--- Vitamin B6 (pyridoxine).
--- Vitamin B9 (folic acid, folacin, folate).
--- Vitamin C (ascorbic acid, L-ascorbic acid).

If the availability of certain vitamins and minerals is limited, the body might not be able to produce adequate levels of neurotransmitters. Below is a list of some neurotransmitters and how the human body synthesizes or makes them.


Acetylcholine
Choline is combined with Acetyl Coenzyme A (Acetyl-CoA),
By the enzyme Choline Acetyltransferase,
To produce Acetylcholine.


Dopamine
Phenylalanine is converted to Tyrosine.
Tyrosine combines with Tyrosine Hydroxylase,
To produce L-dopa.
L-dopa combines with DOPA Decarboxylase,
To produce Dopamine.


Epinephrine
Phenylalanine is converted to Tyrosine.
Tyrosine combines with Tyrosine Hydroxylase,
To produce L-dopa.
L-dopa combines with DOPA Decarboxylase,
To produce Dopamine.
Dopamine combines with Dopamine Beta Hydroxylase,
To produce Norepinephrine.
Norepinephrine combines with PNMT,
To produce Epinephrine.


GABA
Glutamate, with Pyridoxal Phosphate as a cofactor,
Combines with Glutamic Acid Decarboxylase (GAD).
To produce GABA.


Glutamate
Usually obtained via diet, can be synthesized by the body.
Citric Acid is converted to Alpha-Ketoglutaric Acid,
Alpha-Ketoglutaric Acid is converted to Glutamate.


Histamine
Histidine is decarboxylated by L-Histidine Decarboxylase,
To produce Histamine.


Norepinephrine
Phenylalanine is converted to Tyrosine.
Tyrosine combines with Tyrosine Hydroxylase,
To produce L-dopa.
L-dopa combines with DOPA Decarboxylase,
To produce Dopamine.
Dopamine combines with Dopamine Beta Hydroxylase,
To produce Norepinephrine.


Serotonin
Tryptophan is converted to 5-Hydroxytryptophan (5-HTP).
By Tryptophan Hydroxylase and Tryptophan Decarboxylase,
5-Hydroxytryptophan (5-HTP) is then converted to Serotonin.



Notes

1) --- Besides being classified as neurotransmitters, some neurotransmitters may also fall into other categories. For example, having additional functions like acting as hormones.

2) --- Many neurotransmitters share properties with other neurotransmitters. For instance, rather than being associated with a single neurotransmitter, pain can be reduced by increasing the levels of endorphins or dopamine or GABA.

3) --- Some neurotransmitters are made up of only one type, but most are made up of more than that. Dopamine has 5 different receptor subtypes labeled D1, D2, D3, D4, D5. All serve different roles. D2 and D5 are thought to play a role in perception of pain.

Various drugs can have more influence on certain subtypes of receptors. If a drug bound to the dopamine D2 or D5 receptors and triggered them to fire, it would probably have at least some pain relieving properties.

4) --- The information about the neurotransmitters listed above on this page is primarily related to their influence on the brain. Rather than being located only in the brain, neurotransmitter receptors exist in other parts of the body.

The location and density of the receptors is more concentrated in some regions, depending on the purpose of the neurotransmitter. A majority of serotonin is synthesized in the intestine, and stored there, where it plays a role in regulating gastrointestinal functions.

Even within the brain, the location and density of the receptors is different. There are dopamine receptors located throughout the brain, but the density and the subtypes of dopamine receptors (D1, D2, D3, D4, D5) varies in different parts of the brain.


Links
Chemical imbalance in mental health problems.
Doctor George Boeree neurotransmitter page.
Neurotransmitters and drugs.


Image Credits

Chemical structure of acetylcholine by Vaccinationist.
Chemical structure of dopamine by Sunridin.
Chemical structure of GABA by NEUROtiker.
Chemical structure of serotonin by Liaocyed.