Dopamine Neurotransmitter

Dopamine, a neurotransmitter is widely found in animals. It is a type of alkaloid and monoamine compound, called phenethylamine. It works as a neurotransmitter and activates five types of dopamine receptors - D1, D2, D3, D4, and D5, and its variants.

The chemical formula of this compound is C₆H₃(OH)₂-CH₂-CH₂-NH₂; while its chemical name is 4-(2-aminoethyl)benzene-1,2-diol. It is also known by the abbreviation 'DA'. Produced in substantia nigra and ventral tegmental, among other areas in the brain, dopamine is also a neurohormone released by the hypothalamus.

Dopamine has significant roles associated with behavior and cognition, motivation, reward, and voluntary movement. The list also includes roles related to sleep, attention, mood, learning, and inhibition of prolactin production.

Apart from this, it is believed to give a signal to the parts of the brain responsible for learning new behavior. Dopaminergic neurons located in the midbrain, are the main source of dopamine.

How do you feel when you eat your favorite food? Naturally, it is a spontaneous response that we feel good. This feeling of enjoyment is provided by dopamine, which is closely associated with the pleasure system of the brain. It is also released during sexual activity. Food also triggers the release of dopamine.

This neurotransmitter provides a feeling of reinforcement for motivating an individual to perform certain activities. There is a theory that, drugs such as cocaine, amphetamine and nicotine also lead to an increase in the amount of dopamine released.

This neurotransmitter is involved in the control of movements. It is also involved in signaling of error in the prediction of reward, cognition, and motivation. Other reward-seeking behavior associated with this neurotransmitter are addiction, approach, and consumption.

According to a research, when an individual expects a reward, dopaminergic neurons are fired in the brain as a motivational substance. In the effect of the reward being more than what is anticipated, the firing of these neurons increases.

It is also responsible for the flow of information from different areas of the brain to the frontal lobe. If there are problems with its levels, it may lead to a dip in memory, problem solving, and attention. The reduction in the concentration of dopamine in the pre-frontal cortex is said to be responsible for attention deficit disorder.

Neural pathways transmit this pleasure-oriented neurotransmitter from one region to another. There are four major pathways of this transmission and they are as follows:

Mesolimbic Pathway
Dopamine is transmitted from the midbrain, ventral tegmental area (VTA) to the nucleus accumbens in the limbic system through this pathway.

Mesocortical Pathway
Dopamine is transmitted from the VTA to the frontal cortex through this pathway.

Nigrostriatal Pathway
This pathway transmits the neurotransmitter from substantia nigra (structure in the midbrain) to striatum (subcortical part of cerebrum). This pathway is related to motor control and dysfunction or degeneration of the pathway leads to Parkinson's disease.

Tuberoinfundibular Pathway
This pathway, which influences the secretion of certain hormones, including prolactin, transmits dopamine from hypothalamus to the pituitary gland.

These pathways are responsible for the proper functioning of dopamine. That prevents any damage caused to the brain, culminating into a health disorder.

With all these functions and intricacies, it is not surprising that dopamine forms such an important aspect in the functioning of the brain.