Dopamine – The Molecule of Happiness – Free Neuroscience Course

Hello friends!

In our Free Online Neuroscience Course we already talked about neurotransmitters. In summary, neurotransmitters are molecules responsible for communication within the nervous system, that is, they are molecules, chemical substances, that carry the message from one point of the brain to another point of the brain or to another part of the body. To learn more, see here:

What are neurotransmitters?

Today we are going to talk about a very special guy, who brought great discoveries to neuroscience in 1969. His name was Leonard and, because he developed an inflammatory disease in the brain, he became paralyzed. He didn’t show any kind of facial expression and he didn’t have the ability to move around, he couldn’t even move an arm and, also, he couldn’t speak anymore.

Through a system invented by doctors and nurses, he managed to communicate by showing letter by letter and, thus, very slowly, he said what he was thinking and feeling in his extreme state of paralysis. In a few words, he summed up his moment: “a prison with windows but no doors”.

Leonard’s luck began to change when Oliver Sacks, one of the most renowned neuroscientists in the world (at the time still a young doctor), began a brand new type of treatment, using the drug L-Dopa (levodopa), whose consistency is very similar to the dopamine.

Treatment with L-Dopa – Dopamine produced in the laboratory

Not long after starting on L-Dopa, Leonard seemed to have managed to find a door out. Indeed, he seemed to have been reborn! Now he could walk, talk, gesture, eat by himself, I mean, now he could do everything a normal person can do.

The first thing he did was go down to the clinic’s garden and kiss the flowers, smell their perfume. He thanked the doctors and nurses who had cared for him for so long and wrote in his diary: “I feel that I have been saved, resurrected, reborn! I feel like a passionate lover, I broke the barriers that separated me from love. I have a feeling of health that feels divine!”

For him, L-Dopa – which synthesized the properties of dopamine – could only be described as a holy medicine. The medicine “opened my inner windows that were closed. If everyone felt as good as I do, no one would think about conflict or war, about power or possession. Everyone would simply be happy with themselves and others. They would know that heaven is right here on Earth,” Leonard wrote.

The L-Dopa Rebound Effect – The Negative Consequences of Dopamine

However, after only two weeks, Leonard’s emotional state began to change radically. From the state of happiness, joy and contentment, he began to feel anxiety and greed. The impulses of sexuality and quest for power increased and reached difficult levels to deal with, as he wanted to have relationships with the nurses. His sense of power reached such a point that he wrote: “With L-Dopa in my blood there is nothing in the world I cannot do if I want to. L-Dopa is power, it is an irresistible force. L-Dopa is excess energy that consumes itself. L-Dopa gave me the strength I craved.”

The change was swift and radical. If in the first two weeks he was happy and said that peace was a natural desire of human beings (if he had L-Dopa), now he thought the opposite, he thought about power, domination, power. In the weeks that followed, he even became paranoid and manic. He wrote a huge autobiography in 20 days. He spoke with a lot of speed and without control.

The paranoia began to increase, progressively, and he started to think that he was being chased, that ropes were nearby to hang him.

The rebound effect (the opposite effect) of the drug was so strong and so dangerous that the doctor Oliver Sacks decided to completely withdraw its use. After withdrawal, Leonard returned to the initial paralyzed state. He died in 1981, after several unsuccessful attempts to use drugs similar to L-Dopa.

The explanation of dopamine

At the time he prescribed L-Dopa for Leonard, Oliver Sacks, like all other physicians studying neurotransmitters, was just learning how they work. Therefore, the dosage ended up being excessive and the initial positive results turned to the opposite, with paranoia, hallucinations, suicide attempt.

The cause of Leonard’s initial paralysis was inflammation in a very specific part of the brain called the substantia nigra (substantia nigra), which is responsible for the natural production of dopamine. THE substantia nigra it is located in the midbrain and its size is close to that of a fingernail. If we cut the brain crosswise, we will be able to see this region, as it differs from its surroundings by small black spots (hence the substantia nigra).

From Leonard’s story, we can see what the absence of dopamine causes in the organism: the person cannot even lift a finger, stops talking, feels total discouragement. Leonard also teaches us what dopamine exaggeration causes: strong impulses of power and sexuality, paranoia, hallucinations, and even suicide attempts.

But produced by the body naturally and in normal doses, dopamine has its function balanced. Being a small chemical molecule with only 22 atoms similar to a tadpole (head with tail), it is of great importance in the proper functioning of the organism.

Main functions of dopamine

1. Controls sleep and wake cycles
2. Helps with concentration and attention
3. Awakens curiosity for learning
4. Enhances creativity and sexual desire
5. It provokes motivation, optimism, self-confidence

In summary, the dopamine molecule can be considered the molecule of happiness, but more than happiness, we can describe dopamine as the molecule of want, desire, desire.

According to Stefan Klein, a leading German writer on neuroscience: “Dopamine also kicks in when we take on a new task in our professional life, when an attractive person crosses our path in front of us, and especially before the sexual act. When we drink a glass of beer or smoke a cigarette, we also want to create an extraordinary dose of this substance, as both alcohol and nicotine make the brain release more dopamine”.

Thus, this small molecule of 22 atoms performs vital functions for the organism. The main drugs used in the world, in one way or another, provoke the release of dopamine. However, as with Leonard, when a drug is released into the body artificially and in high doses, dopamine causes very negative effects after the initial period of euphoria.

Currently, many researchers are studying the effects of dopamine on mental illness, in particular, schizophrenia. And precisely this will be the subject of our next Lesson in the Free Neuroscience Course.

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