Dopamine is the neurotransmitter which creates the "good feelings" associated with the enjoyment of beauty, the affection you feel for a person, the love you feel for a family member or other loved one, and the extreme reward sensation; sexual climax. The popularity of cocaine stems from the fact that it causes very high levels of dopamine to be trapped in the hypothalamus nerve endings thus giving the person a "reward" sensation many times that of the most extreme natural one. Caffeine is another stimulating drug that, although not as strong as cocaine, increases the dopamine levels to excessive highs and can increase certain mental illnesses. Both caffeine and cocaine disrupts the delicate balance of nerve transmission in your brain’s chemistry and the momentary "high" is eventually replaced by the sad reality that your brain has been severely damaged.
The lack of dopamine availability can cause anhedonia (the lack of ability to feel any pleasure or remorse in life.) It also reduces the person's attention span. For example, a person who has taken cocaine for some time will have used up most of his or her dopamine supply. Their attention span is often reduced to 2 to 3 minutes instead of the usual 50 to 60 minutes. Learning, for such a person, is nearly impossible, and requires a serious lifestyle change.
The brain cells which "manufacture" dopamine use l-phenylalanine as a "raw material" (precursor.) Phenylanine is an essential amino acid found in the brain and blood plasma that can convert in the body to tyrosine, which in turn is used to synthesize dopamine. Sources of phenylanine are high-protein foods such as meat, cottage cheese, and wheat germ. Phenylalanine can also be found in the sugar substitute aspartame, which is sold under the names NutraSweet and Equal. These artificial sweeteners have no calories, do not affect blood sugar, and are generally safe. However they should be avoided entirely by those who have phenylketonuria. Pregnant or lactating women should always seek the advice of their doctor regarding the use of artificial sweeteners.
Increasing your phenylanine levels can be effective for treating mild depression, and particularly in countering fatigue. As many as about 10 to 50 percent of depressed patients have low plasma phenylanine. Eating more phenylanine-rich foods is one of several effective treatments that are available to increase dopamine in your system. Your body can elevate levels of phenylalanine in times of infection or fatigue. Phenylanine levels are lowered by increased caffiene ingestion.
An average adult ingests 4 grams of phenylalanine per day, and may optimally need up to 6 grams daily through supplementation. When supplementation is used the patient also needs to supplement their diet with additional folic acid, niacin and B-6
When phenylalanine is converted to tyrosine by the body, tyrosine increases your resistance to stress and acts as one of the body's natural pain relievers. As mentioned above, tyrosine is used as a building block to create dopamine. It is also used to create norepinephrine, which is chemically related to adrenaline; tyrosine can give dopamine-deficient people the increased energy they are lacking. Foods that contain high amounts of tyrosine include chicken, duck, cottage cheese and wheat germ.
Physicians at Harvard Medical School have pioneered the use of a daily dose of up to 6 grams of tyrosine to decrease symptoms of medication-resistant depression with good results. Tyrosine creates so much raw energy that in extremely large doses (i.e., greater than 20 grams daily), it can reduce your appetite. However, low doses have a less consistent effect. The minimum daily tyrosine requirement is about 1 gram for an average adult.
Dopamine is normally widespread in the brain as well as the rest of the nervous system. This neurotransmitter plays a critical role in the control of movement. It has a stimulating effect on the heart, the circulation, the rate of metabolism, and is able to mobilize many of the body's energy reserves. It helps to modulate brain activity, control coordination and movement, and regulate the flow of information to different areas of the brain. Dopamine is believed to release chemicals that allow us to feel pleasure (e.g., endorphins). A massive disturbance of dopamine regulation in the brain can result in a person no longer being able to respond emotionally or express his or her feelings in an appropriate way (e.g., schizophrenia).
Dopamine Functions in:
Dopamine Deficiencies result in:
Supplements required:
Useful sources of building blocks for dopamine:
Dopamine may have a far broader role in brain function and addiction than previously realized, according to new research from the University of Sheffield and Macquarie University in Sydney, Australia.
The Innovations Report reported March 4, 2005 that the information carried by the neurotransmitter has an impact that goes beyond the reward system. Rather, according to study co-author Paul Overton, dopamine is involved in processing all stimuli which are pertinent to survival.
"Brain systems involved in reward fulfill a vital function in that they underpin the motivation to seek out food, water and all of the other things that we need to survive, and play a central role in learning. We tend to do more of the things that lead to nice outcomes -- that is, we learn according to the effect that our actions have," said Overton.
Overton and colleagues determined that a primitive part of the brain called the superior colliculus provides visual-stimuli information to dopamine messengers. "We concluded that it is unlikely that such a visually primitive structure would be allowed (by evolution) to provide the sensory input to a system which was involved in something as vital as reward. Instead, we propose that, as a "burglar alarm," the colliculus provides information to dopamine cells about the occurrence of biologically important stimuli, which then pass this 'salience' based signal to other brain areas," said Overton.
The finding could explain why people with drug addictions, which disrupts the dopamine system, have such a hard time staying sober in the face of visual stimuli. "Basically, the dopamine malfunction ... could cause the brain to be unable to ignore stimuli associated with the drug, causing relapse and cravings," said Overton.
Overton added: "Less than one percent of the neurons in the brain use dopamine as a neurotransmitter, but any change in its levels can have devastating effects. Too much dopamine can lead to schizophrenia, whereas not enough causes Parkinson's Disease. Drug addicts also have a malfunction in their dopamine systems, so learning more about the way this chemical works could lead to better treatments for a range of conditions."
The research was published in the March 4, 2005 issue of the journal Science.
