All about neurotransmitters
Neurotransmitters are the messenger substances in our brains that transmit signals between brain cells. Some well-known neurotransmitters include melatonin and endorphins. But what exactly are neurotransmitters and what do neurotransmitters have to do with our gut? Let us guide you.
What are neurotransmitters?
Neurotransmitters are signalling chemicals in the brain, also known as messenger substances. This is because they facilitate communication between different brain cells (neurons), with around one hundred thousand signals per second. Neurotransmitters are involved in various parts of our nervous system:
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The parasympathetic nervous system: this part is responsible for the body's rest state (rest & digest).
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The sympathetic nervous system: this part is responsible for the body's action state (fight or flight).
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The enteric nervous system: this is the nervous system of our digestion.
Neurotransmitters play a crucial role in how we think, feel, and act. This makes it important that your neurotransmitters are balanced. When there is an imbalance in neurotransmitters, it can affect various processes in the brain.
What neurotransmitters are there?
Neurotransmitters can be divided into four categories: amino acids, monoamines, peptides, and others. There are more than a hundred neurotransmitters in total, but the best known are:
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Glutamate: Glutamate is involved in memory and learning.
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GABA: GABA helps in reducing pain and stress, and promotes relaxation and calmness.
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Serotonin: Serotonin affects mood, sleep, appetite, and regulates bowel movements. As the 'happiness hormone', it also plays a role in promoting feelings of well-being and happiness.
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Dopamine: Dopamine is involved in motivation, reward, and pleasure.
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Melatonin: Melatonin is involved in regulating the sleep-wake cycle.
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Norepinephrine: Norepinephrine is involved in regulating alertness, attention, and stress response.
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Acetylcholine: Acetylcholine plays a role in memory, attention, and cognitive functions.
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Endorphins: Endorphins are involved in regulating pain and promoting pleasure. They are also associated with the "runner's high" and play a role in reducing stress and promoting relaxation.
Neurotransmitters and the gut
Did you know that some neurotransmitters are partially produced in the gut? This occurs in the enteric nervous system: a complex network of nerve cells and neurotransmitters in the intestines. Some of the main neurotransmitters produced in the gut include serotonin, acetylcholine, GABA, and dopamine. (source)
Our gut communicates with our brain, also known as the brain-gut connection. To produce the right amount of neurotransmitters, good gut health is essential. This ensures that your gut and brain can communicate effectively.
Excitatory and inhibitory neurotransmitters
A neurotransmitter always has one of two roles: activating (exciting) or inhibiting activity in a particular cell. Below you will see which neurotransmitters are excitatory and inhibitory and which category they fall into.
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Neurotransmitter
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Nature
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Category
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Glutamate
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Excitatory
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Amino acid
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GABA
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Inhibitory
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Amino acid
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Serotonin
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Inhibitory
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Monoamine
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Dopamine
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Excitatory/Inhibitory
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Monoamine
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Norepinephrine
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Excitatory
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Monoamine
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Acetylcholine
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Excitatory/Inhibitory
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Other (Choline derivative)
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Endorphins
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Inhibitory
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Peptide
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Melatonin
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Inhibitory
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Other (Melatonin)
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Some neurotransmitters can be both excitatory and inhibitory. This depends on the receiving cell (receptor) they bind to and the brain region in which they operate. Examples of this are dopamine and acetylcholine. Below is a brief explanation of the potential effects depending on where the neurotransmitter binds.
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Neurotransmitter
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Excitatory Effect
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Inhibitory Effect
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Dopamine
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Binds to dopamine D1 receptors and increases neural activity, which can lead to feelings of reward, motivation, and stimulation.
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Binds to dopamine D2 receptors and reduces neural activity, which can be involved in regulating motor functions and controlling impulsive behaviour.
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Acetylcholine
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Binds to muscle cells at the neuromuscular junction and causes muscle contraction, which is involved in voluntary movement of the body.
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Binds to receptors in the basal ganglia and regulates neuron activity, which is important for functions such as movement control, cognition, and memory.
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* Please note that this is a simplified representation of the effects of dopamine and acetylcholine, and there is more complexity and nuance in the functioning of these neurotransmitters in different brain areas and contexts.
