There are different categories of neurotransmitters, with different responsibility and mechanisms of action. Neurotransmitter levels and function are imperial to maintaining homeostasis, and if changed can lead to diseases.
Neurotransmitters are mostly referred to as the body’s chemical messengers. They are the molecules used by the nervous system to transmit messages between neurons, or from neurons to muscles.
it is estimated around 86 billion of neurotransmitter molecules work uninterruptedly to keep our brains functioning, managing everything from our breathing to our heartbeat to our learning and concentration levels. They can also affect a range of psychological functions such as anger, mood, hunger, and satisfaction.
The nervous system moderates the body’s organs, psychological functions, and physical abilities. Nerve cells, also known as neurons, and their neurotransmitters play important roles in this field.
How many types of neurotransmitters are there?
Mostly they are divided into monoamines, amino acids, peptides, Purines, Gasotransmitters, Acetylcholine
Amino Acids
Gamma-aminobutyric acid (GABA)
This naturally occurring amino acid acts as the body’s biggest inhibitory chemical messenger. GABA contributes to vision, motor control, and plays a role in the regulation of stress. Benzodiazepines, which are used to help treat anxiety, function by increasing the efficiency of GABA neurotransmitters, which can elevate feelings of relaxation and calmness.
Glutamate
The most ample neurotransmitter found in the nervous system, glutamate plays a role in cognitive functions such as memory and learning. Excessive amounts of glutamate can cause excitotoxicity resulting in cellular death. This excitotoxicity caused by glutamate build-up is associated with some diseases and brain injuries like Alzheimer’s disease5 , stroke, and epileptic seizures.
Peptides
Oxytocin
This extraordinary hormone acts as a neurotransmitter in the brain. It is produced by the hypothalamus and plays a role in social recognition, bonding, and sexual reproduction. Synthetic oxytocin such as Pitocin is often used as an aid in labor and delivery. Both oxytocin and Pitocin cause the uterus to contract during labor.
Endorphins
These neurotransmitters than inhibit the transmission of pain signals and induces feelings of euphoria. These chemical messengers are produced naturally by the body in response to pain, but they can also be triggered by other activities such as aerobic exercise. For an instance, experiencing a “runner’s high” is an example of pleasurable feelings generated by the production of endorphins.
Monoamines
Epinephrine
Also known as adrenaline, epinephrine is considered both a hormone and a neurotransmitter. Generally, epinephrine is a stress hormone that is released by the adrenal system. However, it functions as a neurotransmitter in the brain.
Norepinephrine
This naturally occurring chemical is a neurotransmitter that plays an important role in alertness is involved in the body’s fight or flight response. Its role is to help mobilize the body and brain to take action in times of danger or stress. Levels of this neurotransmitter are typically lowest during sleep and highest during times of stress.
Histamine
This organic compound acts as a neurotransmitter in the brain and spinal cord. It plays a role in allergic reactions and is produced as part of the immune system’s response to pathogens.
Dopamine
Commonly known as the feel-good neurotransmitter, dopamine is involved in reward, motivation, and additions. Several types of addictive drugs increase dopamine levels in the brain. This chemical messenger also plays an important role in the coordination of body movements. Parkinson’s disease, which is a degenerative disease that results in tremors and motor movement impairments, is caused by the loss of dopamine-generating neurons in the brain.
Serotonin
A hormone and neurotransmitter, serotonin plays an important role in regulating and modulating mood, sleep, anxiety, sexuality, and appetite. Selective serotonin reuptake inhibitors (SSRIs) are a type of antidepressant medication commonly prescribed to treat depression, anxiety, panic disorder, and panic attacks. SSRIs work to balance serotonin levels by blocking the reuptake of serotonin in the brain, which can help improve mood and reduce feelings of anxiety.
Purines
Adenosine
This naturally occurring chemical acts as a neuromodulator in the brain and is involved in suppressing arousing and improving sleep.
Adenosine triphosphate (ATP)
Considered to be the energy currency of life, ATP acts as a neurotransmitter in the central and peripheral nervous systems.12 It plays a role in autonomic control, sensory transduction, and communication with glial cells. Research suggests it may also have a part in some neurological problems including pain, trauma, and neurodegenerative disorders.
Gasotransmitters
Nitric oxide
This compound plays a role in affecting smooth muscles, relaxing them to allow blood vessels to dilate and increase blood flow to certain areas of the body.
Carbon monoxide
This colorless, odorless gas can have toxic and potentially fatal effects when people are exposed to high levels of the substance. However, it is also produced naturally by the body where it acts as a neurotransmitter that helps modulate the body’s inflammatory response.
Acetylcholine
Acetylcholine
This is the only neurotransmitter in its class. Found in both the central and peripheral nervous systems, it is the primary neurotransmitter associated with motor neurons. It plays a role in muscle movements as well as memory and learning.
How do neurotransmitters work?
When a cell is activated, these neurochemicals are released into the synapse from specified pouches clustered near the cell membrane called synaptic vesicles. designated receptors on neighboring cells can then take up the neurotransmitters, which can rev up or cool down the signal being passed along a specific circuit.
A neurotransmitter affects a neuron in one of three ways: excitatory, inhibitory or modulatory.
An excitatory transmitter strengthens the genesis of an electrical signal called an action potential in the receiving neuron, while an inhibitory transmitter prevents it. Whether a neurotransmitter is excitatory or inhibitory depends on the receptor it binds to. Neuromodulators are quite different, as they are not restricted to the synaptic cleft between two neurons, and so can affect large numbers of neurons at once. Neuromodulators therefore regulate populations of neurons, while also operating over a slower time period than excitatory and inhibitory transmitters.
Receptors and neurotransmitters act like a lock-and-key system. Just as it takes the right key to open a specific lock, a neurotransmitter (the key) will only bind to a specific receptor (the lock). If the neurotransmitter is able to work on the receptor site, it triggers changes in the receiving cell.
What happens after neurotransmitters do their work?
Once the neurotransmitter has had the designed effect, its activity can be stopped by three techniques:
Degradation
An enzyme morphs the structure of the neurotransmitter so it can’t be recognized by the receptor
Diffusion
The neurotransmitter sways away from the receptor
Reuptake
The entire neurotransmitter molecule is taken back up by the axon of the neuron that released it.