Neurotransmitters: The Brain’s Messaging System

Whether you are learning a new fact or driving your car down the highway, tasks executed by your brain rely on the smooth and efficient release of neurotransmitters – chemicals that send messages from one brain cell to another.

Neurotransmitters are the central nervous system’s primary method of communication between the roughly 1000 trillion connections (between the 100 billion neurons) that make up the human brain. Neurotransmitters transfer the appropriate information for thoughts, emotions, movements, hormones, and every other conscious and unconscious action that we take every day (2,3)!

While we might not consciously think of how neurotransmitters might affect our day-to-day, they are functionally integrated into the actions of every cell in our body. The culmination of which is what we call “life” and how we experience it. The brain and body contain a multitude of different neurotransmitters. However, there are four neurotransmitters that are of particular interest, because they govern our body’s most essential and primary functions.

These four neurotransmitters are called:

  1. Serotonin
  2. GABA (gamma-Aminobutyric acid)
  3. Dopamine
  4. Norepinephrine


Serotonin is an important molecule for influencing mental health and brain function, as it impacts every part of your body, from your emotions to your motor skills.   It plays multiple roles in the brain’s biochemistry including

  • Maintaining a balanced mood
  • Boosting self-confidence and social engagement
  • Facilitating sustained and deep sleep
  • Supporting a healthy appetite
  • Decreasing worries and concerns

Additionally, serotonin is associated with learning and memory. Interestingly, although serotonin is manufactured in the brain, where it performs its primary functions, it is estimated that about 90% of our serotonin supply is found in the digestive tract and in blood platelets.

Serotonin is connected directly to mood disorders and is often cited in their diagnosis. Research suggests that low levels of serotonin are to blame for disorders such as depression, PMS, and insomnia (7). Serotonin levels are also directly affected by a person’s exposure to stress, diet, sleep duration, and certain prescription medications.


GABA is an amino acid that also functions as a neurotransmitter that is considered the brain’s main “calming” neurotransmitter. [ GABA and serotonin are two of the more inhibitory neurotransmitters (4,6).] It is essential for brain metabolism and works to decrease neuronal activity and inhibit nerve cells from excess firing.

Although GABA’s primary responsibility is to help regulate the activity of neurons, it is also very important for the maturation of new nerve cells (neurogenesis). In addition, GABA has mild relaxation properties and can enhance mood and support sleep.

Most sedative drugs work (think sleep aids: Ambien, benzos: Xanax) work on the GABA system to elicit their effects. Low GABA levels often result in restlessness, irritability, stress, and anxiety. On the other hand, high GABA levels tend to result in sleepiness or sluggishness.


Often called the “motivation molecule,” dopamine provides the drive and focus you need to be productive. Dopamine primarily affects motivation, interest, and drive. It is unique in the fact that it can be both excitatory and inhibitory (1). It is heavily involved with:

  • Attention span
  • Focus
  • Motivation
  • Motor movements
  • The ability to experience pleasure

When dopamine levels are low, we often have very little motivation to perform tasks, or do much of anything. This can often lead to addictive or dependency type behavior, in an attempt to elicit a dopamine response. On the other hand, excessive dopamine can lead to an abnormally increased heart rate, headaches and anxiety. Furthermore, abnormalities in dopamine regulation are suggested to play a role in psychiatric disorders like schizophrenia (1).


Norepinephrine is produced by the adrenal gland as well as in sympathetic nerve endings; and can be synthesized from dopamine. One of its primary uses is to stimulate our fight or flight response. In this case, norepinephrine is released in a burst, which can spur a greater muscular and hormonal response. Conversely, and under normal circumstances, norepinephrine is released in a tonic manner, which can aid sleep, reduce inflammation, and sustain concentration (5).

Better brain chemistry = better quality of life.

When your neurotransmitters are out of balance, you may experience difficulties in school, at work, at home, in relationships, or within yourself. The brain is constantly seeking to keep itself balanced through increasing or decreasing amounts of these substances. The good news is there are things you can do to improve your brain chemistry and improve your brain health.


  1. Brisch, R., Saniotis, A., Wolf, R., Bielau, H., Bernstein, H. G., Steiner, J., … & Henneberg, M. (2014). The role of dopamine in schizophrenia from a neurobiological and evolutionary perspective: old fashioned, but still in vogue. Frontiers in psychiatry5, 47.
  2. Ciranna, Á. (2006). Serotonin as a modulator of glutamate-and GABA-mediated neurotransmission: implications in physiological functions and in pathology. Current neuropharmacology4(2), 101-114.
  3. Martin, J. B. (1980, September). Functions of central nervous system neurotransmitters in regulation of growth hormone secretion. In Federation proceedings(Vol. 39, No. 11, pp. 2902-2906).
  4. McCormick, D. A. (1989). GABA as an inhibitory neurotransmitter in human cerebral cortex. Journal of neurophysiology62(5), 1018-1027.
  5. Mitchell, H. A., & Weinshenker, D. (2010). Good night and good luck: norepinephrine in sleep pharmacology. Biochemical pharmacology79(6), 801-809.
  6. Neurotransmitters – Neurotransmitters tests & supplements. (n.d.). Retrieved from
  7. Young, S. N., & Leyton, M. (2002). The role of serotonin in human mood and social interaction: insight from altered tryptophan levels. Pharmacology Biochemistry and Behavior71(4), 857-865.







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