Monoamine” is a term used to describe neurotransmitters that act to transmit signals from a nerve or neuron to a cell. They play an important role in brain metabolism or processing and elicit many different behaviors. Monoamines fall into two categories – catecholamines and indolamines – and within each class are different neurotransmitters. Catecholamines are made up of neurotransmitters such as adrenaline, noradrenaline and dopamine, and indolamines include the neurotransmitter serotonin.
The chemicals called catecholamines are created within the body of amino acids such as phenylalanine and tyrosine. Amino acids are an essential element for proteins within the body. Proteins are produced within the human body for 20 different amino acids, nine of which have been classified as “essential” or indispensable amino acids. They are given this label because the body alone is unable to produce them but depends heavily on them. These amino acids are supplied to the body through food.
Catecholamines are a class of monoamines, including adrenaline, noradrenaline and dopamine. These neurotransmitters usually operate within the sympathetic and central nervous system and have different roles. Under a microscope, the chemical structure of a catecholamine consisting of a benzene ring with amine and hydroxyl side chains.
Adrenaline is released by the adrenal glands and stimulates the sympathetic nervous system, creating feelings such as excitement, shock and fear. Norepinephrine is the precursor of adrenaline and functions to mediate the signaling of these nerve impulses. Dopamine is the precursor to norepinephrine. The highest concentration of dopamine is found within the basal ganglia, an area of the brain involved in regulating subconscious voluntary movement.
Indolamines are another class of monoamines and consist of the neurotransmitter serotonin. This chemical is widespread throughout the body’s tissue. It is particularly found in the brain, in the lining of the gastrointestinal tract and in blood platelets. Serotonin has the function of controlling states of consciousness and mood, and works to inhibit gastric secretions from the gastrointestinal tract.
Monoamines are neuromodulators, which means they are able to stimulate many neurons that are far from each other. As a result of this, monoamines are capable of producing many different behavioral results. Monoamine are broken down by natural enzymes called monoamine oxidase (MAO).