Where two neurons meet, a very small gap (synapse) exists between them. The electrical impulse traveling along the axon of the neuron must convert into a chemical signal to bridge this gap. The chemicals that do this are called neurotransmitters. These so-called chemical messengers are involved in our different responses to situations.
Your emotions depend on fluctuating levels of neurotransmitters, which cause the activation of different parts of the brain responsible for different moods or activate parts of the brain that trigger the stimulation of the autonomic nervous system.
What are the main Neurotransmitters?
There are more than 40 neurotransmitters in the human nervous system; some of the most important are:
Adrenaline
Released by the adrenal glands that sit on top of each kidney. Adrenaline increases the flow of blood to our muscles, raises our heart and dilates our pupils. It is crucial in our flight-or-fight survival response.
Noradrenaline
Similar to adrenaline, the release of this chemical can result in increased levels of alertness, helping to prime us for action if needed. It also increases our blood pressure and widens our air passages.
Dopamine
This is the addictive reward chemical that your brain craves. It serves to motivate you to seek out the things you need for your survival. We can sometimes find ourselves enslaved by this ancient reward mechanism.
Oxytocin
Also known as the ‘cuddle hormone’, oxytocin is released when you are close to another person. It’s essential for making strong social bonds, and it’s also a key part of why we want to trust people.
GABA
Responsible for regulating muscle tone, Gamma-Aminobutyric acid (GABA) also regulates the communication between brain cells. It can calm us down by reducing the rate at which our neurons fire.
Acetylcholine
This is the main neurotransmitter in the parasympathetic nervous system that slows our heart rate, contracts smooth muscles, dilates blood vessels and increases bodily secretions. The parasympathetic nervous system is the part of the autonomic nervous system that affects the organs in such a way that the body can enter a state of rest and recovery. It therefore has an opposite function to the other part of the autonomic nervous system, the orthosympathetic nervous system.
Glutamate
The most abundant neurotransmitter in the vertebrate nervous system, glutamate is used by nerve cells to transmit signals to other cells. Too much of it can cause cognitive impairments.
Endorphins
Triggered by the sensation of pain, endorphins work to inhibit the transmission of pain signals. Capable of producing a sense of euphoria, studies have suggested endorphins may also be stimulated by laughter.
Serotonin
Serotonin is linked to our wellbeing and happiness, and our levels of it are affected by exercise and exposure to sunlight. It also helps regulate our mood balance, sleep cycle and digestion.