What Are Neurotransmitters: Understanding the Brain’s Chemical Messengers

Many of us talk about serotonin or dopamine in terms of pleasure, but may not quite understand exactly what they are or what they do. So, exactly what are neurotransmitters? In this article, we'll take a basic but comprehensive look at neurotransmitters, the body's chemical messengers and bridge the central nervous system to all other bodily systems.

Introduction to Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals between neurons in the nervous system, as well as from neurons to a muscle or gland cell. The messages carried by neurotransmitter molecules control the systems in the body, allowing your heart to beat, muscle contraction to move your limbs, and your body to input and respond to information received from all areas of the body, as well as your external environment.

Some common neurotransmitters include:

• Dopamine
• Serotonin
• Glutamate
• Gamma aminobutyric acid (GABA)

How Neurotransmitters Work

The human body has billions of nerve cells. These nerve cells are typically made up of three parts:

• Cell body. This area maintains the function of the nerve cell and produces neurotransmitter molecules
• Axon. Carries electrical signal along the nerve cells to the axon terminal
• Axon terminal. In the terminal, electrical messages are changed to chemical signals using neurotransmitters to communicate with other nerve cells, muscle cells, or organs

Neurotransmitters are housed in the axon terminal, and stored within sacs called synaptic vesicles, which hold thousands of neurotransmitter molecules. Neurotransmitters are released from synaptic vesicles in the presynaptic neuron into the synaptic cleft. They then bind to specific receptors on the postsynaptic membrane, triggering a response.

The effect of the neurotransmitter is determined by the receptor it binds to, which can be excitatory, inhibitory, or modulatory.

Types of Neurotransmitters

Neurotransmitters can be classified into amino acids, peptides, and monoamines, and they may have one of three actions depending on the type of neurotransmitter. These include:

Excitatory Neurotransmitters

Excitatory neurotransmitters cause the neuron to send the message "excite" it, and continue the message along to the next cell. Excitatory neurotransmitters include amino acid glutamate, as well as epinephrine and norepinephrine.

Inhibitory Neurotransmitters

Inhibitory neurotransmitters play the part of stopping the chemical message from continuing. Inhibitory neurotransmitters include gamma aminobutyric acid (GABA), and serotonin.

Modulatory Neurotransmitters

Modulatory neurotransmitters adjust other chemical messengers. They affect a large number of neurons simultaneously, and tweak how cells communicate at the synapse.

Sub-Types of Neurotransmitters

Scientists group neurotransmitter based on their chemical nature. Although over a hundred have been discovered so far, experts suspect that many others may exist.

Amino acids neurotransmitters play a role in most functions of the nervous system. Some amino acids neurotransmitters include gamma aminobutyric acid, the most common inhibitory neurotransmitter of the nervous system, and particularly in the brain. Glutamate is the most common excitatory neurotransmitter in the nervous system. Glycine is the most common inhibitory neurotransmitter in the spinal cord.

Monoamine transmitters play a number of roles in the nervous system, but especially in the brain. They regulate appetite, sleep, attention, consciousness, and emotion. Monoamines include serotonin, histamine, dopamine, epinephrine, and norepinephrine.

Peptide neurotransmitters are chains of amino acids and include endorphins, a natural pain reliever.

Acetylcholine is one of the excitatory neurotransmitters and is responsible for many functions of the central nervous system (the brain and spinal cord). Acetylcholine and acetylcholine receptors are used by most neurons in the autonomic nervous system, which regulate automatic systems like heart rate, gut motility, and blood pressure. It also plays a role in motor neurons, motivation, sleep, and learning.

Neurotransmitter Functions and Disorders

Neurotransmitters play a crucial role in controlling various bodily functions, such as movement, sensation, perception, and cognition. They also regulate the autonomic nervous system. The autonomic nervous system controls involuntary functions like heart rate and digestion.

Neurological and Neurodegenerative Disorders

When there are imbalances or abnormalities in neurotransmitter levels or function, it has been linked to a number of neurological and neurodegenerative disorders like Parkinson's disease, depression, and Alzheimer's disease.

Some issues that can affect these chemical messengers include:

• Inflammation or damage to the synaptic cleft can cause the receiving neuron to not take enough of the neurotransmitter molecules
• An insufficient amount (or too much) of a neurotransmitter is produced
• Enzymes can limit the number of neurotransmitters reaching their target cell
• The neurotransmitter can be absorbed too quickly

When neurotransmitter function is effected, a number of chronic illnesses may arise. There have been possible links shown between too much serotonin and autism spectrum disorder. Mania has been linked to too much dopamine activity and abnormal glutamate transmission. Dementia can result when there is not enough acetylcholine being produced. Dopamine receptors can play a role in ADHD, bipolar disorder, or Parkinson's disease.

Medications that influence neurotransmitter action, such as selective serotonin reuptake inhibitors, are often used to treat many of these disorders.

Detection and Modulation

Detecting neurotransmitter imbalances or abnormalities in the nerve cells, synaptic cleft, presynaptic neuron, synaptic vesicles, and postsynaptic membrane is crucial for developing effective treatments for neurological and neurodegenerative disorders.

Modulating neurotransmitter levels or function through pharmacological or therapeutic interventions can help alleviate symptoms and improve quality of life.

Importance of Neurotransmitters

Neurotransmitters play a vital role in maintaining brain health and the function of the central nervous system. The brain and spinal cord, motor neurons of the peripheral nervous system, and all other systems of the body are also affected by these chemical messengers.

Understanding how excitatory, modulatory, and inhibitory neurotransmitters work and their role in neurological and neurodegenerative disorders can lead to the development of more effective treatments and therapies.

Further research is needed to uncover the complex mechanisms of neurotransmitters and their role in brain function and disease.

Addressing Brain Health and the Nervous System in Brooklyn

Many of the malfunctions that affect the chemical messengers of the brain and spinal cord can lead to mental health disorders that may be treated with both medication and talk therapy.

At Williamsburg Therapy Group, our team of doctoral-level psychotherapists offers a number of evidence-based therapeutic approaches that can offer tools for reducing stress, addressing the symptoms of an unbalanced nervous system, and increasing life satisfaction overall.

If you have been diagnosed with depression, bipolar disorder, anxiety, or other mood disorders, give us a call today, and our patient coordinator will help you find the right therapist to help you identify any challenges and create a personalized treatment plan to put you on the path toward improved mental health and wellness.