Dopamine functions both as a neurotransmitter and a hormone. It helps control physical movement and also helps regulate information flow to the higher levels of the brain, thus having low levels of dopamine may impact working memory and ability to focus. You might know someone who takes Ritalin. Well, that is a drug which is sometimes prescribed for people who have difficulty focusing because it counters the low levels of dopamine.
When tripled up with serotonin and endorphin, dopamine balances out high levels of norepinephrine, which can cause aggression. These three neurotransmitters also release into the brain when stimulated by exercise (think of a runner’s high, for instance), listening to music you like, smelling smells you enjoy (like freshly baked cookies), and receiving positive feedback, so you can understand why dopamine, serotonin and endorphin are thought of as the “feel good” chemicals. 🙂
There is a down side, though, to having naturally produced “feel good” chemicals in the brain. External elements often influence us and how we feel, and some of these elements can have negative effects on the body, such as too much alcohol or indulgence in other types of drugs. This is where addiction comes in to the story, as you can read in this University of Texas at Austin article.
From the Surfari wiki (which I co-authored with a colleague): Did you know that your brain is about 80 percent water? To keep it alert, it is good to drink water throughout the day. Another type of food that feeds your brain is protein. Protein provides amino acids, which help produce dopamine and norepinephrine. Sources of protein include yogurt and cheese (hey, this sounds like dairy products!), animal foods (chicken, meat, fish and eggs), and for those of you who prefer vegetarian foods (beans, lentils, nuts and seeds).
In Parkinson’s’ disease there are decreased quantities of dopamine which result in physical movements that are constant and jerky. An insufficient quantity of dopamine is also associated with Schizophrenia. The pharmaceutical L-dopa can sometimes help neurons to continue producing dopamine.