#monoamines

In our body, neurotransmitters are essential for the correct execution of all its functions, thanks to them, our nervous system has communication throughout the body. Within the group of neurotransmitters are monoamines. Monoamines are characterized by being distributed in both the central nervous system and the peripheral nervous system. Their functions are diverse, but broadly speaking, they are responsible for neuromodulation.

They are responsible for transmitting synaptic information throughout the nervous system, to carry out each of our activities as human beings. Although they are microscopic, they play an important role in the regulation of emotional states, attention, and visceral functions. A disorder in the work of neuromodulation of monoamines is reflected in psychiatric disorders, and in fact, the treatment of these diseases affects one or more stages of the synthesis of monoamines, their storage, or their degradation.

Monoamines are produced by various neuron systems in the brain. Therefore, monoaminergic neurons serve to modulate the function of large regions of the brain, increasing or decreasing the activity of certain brain activities.

Classification of Monoamines

Monoamines are classified into two groups: indoleamine and catecholamines. Among the first are norepinephrine, dopamine, and adrenaline, while in the second group, we only find serotonin.

Catecholamines

At the chemical level, these neurotransmitters are characterized by the presence of a catechol (an organic compound that contains a benzene ring and two hydroxyl groups) and an amine in the side chain. They are derived from the amino acid tyrosine, which we obtain through protein-rich foods such as dairy, bananas, avocados, or nuts.

Dopamine

Dopamine participates in multiple brain functions, among which we will mention learning and memory, motivation and reward for pleasant stimuli (it induces the repetition of behaviours that bring us pleasure such as food, sex, and drugs), sleep, humour, attention, motor activity and regulation of prolactin secretion (inhibits its production at the pituitary level).

The brain's reward systems are activated in the presence of dopamine and respond to emotionally charged stimuli (either positive or negative, that is, achieve something good or avoid something bad). One of the most powerful structures in this area is the nucleus accumbens, considered the main pleasure centre in the brain.

Thus, when dopamine is released in these systems, we feel pleasure, well-being, and relaxation. They are sensations of great importance throughout our evolution and are present in the basic needs of survival (for example, food and sex). Dopamine doesn't always stay at optimal levels. When an imbalance of this neurotransmitter occurs, the effects can be diverse, even leading to disorders.

Adrenaline

Also known as epinephrine, is a hormone and neurotransmitter produced by the adrenal glands, which are on top of the kidneys. The body produces it and stores it to release it in situations of alarm, stress, fear, or danger. It helps the body to better prepare and defend itself in risky situations. 

For all this, adrenaline can be seen as a means of survival in times of danger or stress. It is in these situations when the hypothalamus orders the secretion of epinephrine to the glands that immediately respond by filtering it in the circulatory system that distributes it throughout the body, causing different effects that together are those that carry what is colloquially known as "adrenaline rush". Adrenaline raises blood pressure, increases blood glucose or sugar, increases heartbeat, and dilates the bronchial tubes. All these effects prepare the body to react better to dangers.

Noradrenaline

Likewise, norepinephrine does not only act as a neurotransmitter but also exerts functions in the endocrine system, being produced both at the brain and adrenal level. When we are under continual stress, our adrenal glands never stop pumping stress hormones (adrenaline and norepinephrine), and this has profound effects on our physical and mental health.

It participates both in the transmission of messages between areas of the brain and with the outside, having great participation in the sympathetic nervous system.

When this hormone is released, it increases the heart rate and blood pressure. It also produces a pupillary dilation and helps to improve the passage of air into the lungs. Norepinephrine prevents the narrowing of blood vessels in visceral organs. It stimulates a type of receptor known as alpha receptors, which cause muscle contraction and narrowing of the blood vessels in these areas. Due to the narrowing of blood vessels in the periphery, blood is redirected to vital organs such as the heart and brain.

Indoleamines

They are neurotransmitters that contain an indole group. At the chemical level, the indole group is a heterocyclic organic compound, solid, and colourless.

Serotonin

Traditionally, it has been named after the "happiness particle" or the "happiness neurotransmitter." The reason is that serotonin is the main one in charge of regulating our mood. This neurotransmitter, which plays a fundamental role in regulating our intestinal function, has the ability to create the chemical reactions necessary to increase our feeling of well-being and satisfaction.

Medicine (Forensic Toxicology)

Toxicology of Monoamine Active Drugs

Teva Wins Breakthrough Therapy Designation for Tardive Dyskinesia Candidate

FDAnews Drug Daily Bulletin

Pharmaceuticals / Submissions and Approvals

Teva Wins Breakthrough Therapy Designation for Tardive Dyskinesia Candidate Nov. 16, 2015

Teva Pharmaceutical Industries has won the FDA’s breakthrough therapy designation for SD-809 for the treatment of moderate to severe tardive dyskinesia.

An oral, small molecule inhibitor of vesicular monoamine 2 transporter, SD-809…

By diving deeper into the science of bioactive lipids, we begin to unearth the potential role of the endocannabinoid system (ECS) in stress and fear responses.

This article is sponsored by CannaVest, one of the leading suppliers of agricultural hemp-derived CBD from seed to finished products.

Monoamines such as dopamine, serotonin, and norepinephrine have been the focus of treatments for anxiety, stress, fear and related emotional stresses. However, their efficacy has been limited.

More recent research has begun to highlight other neurochemical systems, including cytokines, peptides, and bioactive lipids. Delving deeper into these bioactive lipids, the potential role for the endocannabinoid system (ECS) has been revealed.

The ECS is a complex physiologic network within the human body comprised of cannabinoid receptors (CB1 and CB2). There are endogenous cannabinoid compounds such as anandamide and 2-AG, and their respective enzymes responsible for maintaining balance in the system. This is done by regulating the synthesis and breakdown of the active endocannabinoid compounds. 

Sure enough, the cannabinoid receptors and other biomechanics necessary for synthesizing and generating cannabinoids are present within areas of the brain known to control emotional behavior, mood, stress, and fear. These structures include the prefrontal cortex, amygdala, hippocampus, and periaqueductal gray (PAG) of the midbrain.

Following is an article explaining depression's chemical Imbalance.The article is by Rick Nauert PhD Senior News Editor and was reviewed by John M. Grohol, Psy.D. on November 10, 2006. The source is the Centre for Addiction and Mental Health

For over three decades, scientists have attributed a chemical imbalance in the brain as the source of major depression. Now, a new study provides an explanation of how this “chemical imbalance” occurs.

Major depression is a disease that impacts approximately 5% of people globally. For over 30 years, scientists believed that monoamines– mood-related chemicals such as serotonin, norepinephrine and dopamine– are low in the brain during major depressive episodes. This is commonly referred to as a “chemical imbalance”. However, no one had ever found a convincing explanation for monoamine loss, until now.

This study by the Canadian-based Centre for Addiction and Mental Health (CAMH) is published in the November Archives of General Psychiatry.

Dr. Jeffrey Meyer investigated whether brain monoamine oxidase A (MAO-A) — an enzyme that breaks down chemicals like serotonin, norepinephrine and dopamine– was higher in those with untreated depression. The results showed that in major depression MAO-A was significantly higher in every brain region that the scientists investigated. On average, MAO-A was 34% higher.

According to Dr. Meyer, “In major depression, higher levels of MAO-A is the primary process that lowers monoamine levels. Having more MAO-A leads to greater breakdown of key chemicals like serotonin.”

This study by the Canadian-based Centre for Addiction and Mental Health (CAMH) includes a detailed new monoamine model of depression, based upon this work as well as four previous publications from Dr. Meyer and collaborators at CAMH.

Said Dr. Meyer, “A key barrier to making advances in treating depression is a lack of precise disease models. Having disease model is like having a map. Once you have that map you can really begin to understand how an illness like depression works, and offer more targeted and effective treatment.”

A second part of this new model is that monoamine transporters have an important role in removing monoamines away from active sites. Having more of a monoamine transporter is not helpful as it removes more monoamine — for example if one has more serotonin transporter, one would additionally lose more serotonin during depression.

“An important aspect of our advanced monoamine model is that individuals with depression lose chemicals like serotonin and dopamine at different rates based upon transporter density. This helps explain why one person with depression may experience loss of appetite while another may not. And some people have more severe symptoms than others,” said Dr. Meyer.

This advanced monoamine model of depression is a huge step forward in the disease frontier. It brings the study of mental illness closer to the advancements seen in research into physical illness such as cardiac disease, and offers one of the most comprehensive disease models in mental illness.