2023-09-14 16:47:36
What are neurotransmitters?
And neurotransmitter is an organic compound that ensures the transmission of information from one nerve cell (or neuron) to another.
And neurone generates and propagates an electrical signal along its axon. Then it transmits this “action potential” to a second neuron and so on. At the level of the synapse which separates the two neurons are released neurotransmitters which bind to the receptors of the receiving neuron. The signal can then stimulate or inhibit the target cell depending on the neurotransmitter and receptor involved.
What is the role of a neurotransmitter?
Neurotransmitters allow neurons to communicate with each other but also to send messages from the brain to the rest of the body. Indeed, the muscles themselves receive signals from neurotransmitters. They are at the origin of our feelings and certain of our bodily reactions.
Neurotransmitters have very different roles. Some provide calm and tranquility. Others, on the contrary, raise the heart rate and put you in a state of hypervigilance. Finally, there are those which bring immediate pleasure or even long-term well-being.
A lack or, on the contrary, an excess of one of these mediators can explain the development of certain neurological or psychiatric pathologies.
What are the main neurotransmitters?
There are more than a hundred different neurotransmitters, around twenty of which are of major importance. Here is a non-exhaustive list of the main neurotransmitters that you have probably already heard of.
Glutamate and aspartate, the main exciters of the brain
The glutamate and theaspartate are the main excitatory neurotransmitters of the adult nervous system. Their role is also important during embryonic brain development. One of their receptors is the N-methyl-D-aspartate (NMDA) receptor. In excess, glutamate is toxic to the nervous system.
GABA protects us from anxiety
L’gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain. It attaches to the GABA-A and GABA-B receptors. It provides afeeling of calm and serenity.
THE anxiety disorders are symptomatic of a deficiency of this neurotransmitter. Takinganxiolotics (benzodiazepines) helps to soothe anxiety. These drugs act on GABA just like recent antiepileptics and barbiturates.
Toxic substances like picrotoxin and muscimol also target GABA.
Finally thealcohol also binds to GABA receptors providing a relaxed state which can lead to strong dependence.
Serotonin, a guarantee once morest depression
The serotonin is synthesized from the tryptophanan amino acid provided by food.
This neurotransmitter acts in particular in the regulation of mood, sleep-wake alternation, appetite, pain perception, body temperature, sexual desire and alertness.
Serotonin receptors are called 5-HT.
Certain medications called selective serotonin receptor agonists or triptans can stop migraine attacks. On the other hand the selective serotonin reuptake inhibitors (SSRIs) or serotonergic antidepressants can treat many psychological illnesses such as depression or anxiety disorders.
Acetylcholine: its deficiency involved in Alzheimer’s disease
It is a very important neurotransmitter whose receptors (called “nicotinic” and “muscarinic”) are widely present within the nervous system.
L’acetylcholine is synthesized from choline and acetyl CoA.
This neurotransmitter is an excitator that triggers muscle contraction and stimulates the excretion of certain hormones. At the level of our brain it is involved in awareness and attention.
Acetylcholine levels are thought to be greatly reduced in Alzheimer’s disease.
The nicotine contained in cigarettes is an agonist of this neurotransmitter and binds to its receptors leading to strong dependence.
Dopamine, the pleasure molecule
The dopamine is a neurotransmitter made from an amino acid: tyrosine. It binds to D receptors.
Dopamine plays a crucial role in many brain functions, including mood regulation, motivation or reward. It provides a feeling of immediate pleasure when carrying out essential actions such as eating or reproducing, for example.
Disturbed dopamine levels are implicated in certain mental illnesses such as bipolar disorder or schizophrenia. On the other hand, a dopamine deficiency can cause motor disorders such as Parkinson’s disease or attention deficit disorder (ADHD). In these cases, medications help regulate dopamine levels.
It should be noted that dopamine also acts as a hormone whose main function is to inhibit the release of prolactin from the pituitary gland. Dopamine is also a precursor of norepinephrine itself, allowing the production of adrenaline in cases of stress.
Noradrenaline, a precursor of adrenaline
This catecholamine acts as both a neurotransmitter and an adrenergic hormone. It plays a role in attention, wakefulness, sleep, dreaming, sensitivity to emotional signals (fear, pleasure, sexual desire) and learning.
It is also necessary in cases stress orphysical activity. Just like adrenaline, of which it is the precursor, it has the effect of preparing the body for a possible escape (in response to stress) or intense effort (in the case of physical activity). It binds to alpha and beta adrenergic receptors, inducing an increase in heart rate and blood pressure, a relaxation of intestinal transit, a dilation of the pupils or even an increase in alertness.
Endorphin and enkephalins, allies once morest pain
L’endorphins and the one-size-fits-all (which include met-enkephalin and leu-enkephalin) bind to opiate receptors. They are neurotransmitters playing the role of an endogenous morphine, notably pain inhibitor. These neurotransmitters are also associated with a feeling of well-being and fullness. Their release increases during physical activity.
Oxytocin, a guarantee of lasting love
L’oxytocin is a neurotransmitter and hormone that affects bodily functions. She :
- causes uterine contractions during childbirth;
- promotes the emotional bond between mother and child immediately following birth;
- allows breastfeeding by stimulating the flow of breast milk…
Additionally, oxytocin has a vital role in establishing connections of loyalty and trust. In other words, strong friendships and family ties involve the production of oxytocin. Oxytocin is also essential for stabilizing a romantic relationship. They say it’s the molecule of love and attachment.
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