Dopamine is a chemical messenger responsible for transmitting signals between nerve cells. It is very prominent in the transmission from the nerve cells of the substantia nigra to those of the corpus striatum, to facilitate smooth, purposeful muscle activity. Dopamine is the immediate metabolic precursor of norepinephrine (also called noradrenaline) and epinephrine (also called adrenaline), i.e., it is the raw material from which the other two chemicals are made. Dopamine can have either an excitatory or inhibitory effect on nerve cells, depending on the characteristics of the protein it combines with.
Dopamine is associated with the perception of pain and pleasure. Increased dopamine in the frontal lobes lessens pain and increases pleasure. If a person naturally has a higher level of dopamine because of a good personality, good genes and a diet, he or she tends to tolerate pain better. That is why even when different people have the same kind of arthritis or back problems, some people have unbearable pain while others have no pain at all. On the TV show House, the foster parents of a girl were suspected of abusing her. Although her body showed many signs of physical abuse, she did not complain about the pain to the physician. One of the residents used a bucket of ice to test her tolerance to coldness. Although the resident started screaming due to the extreme pain induced by the cold ice when he took the test, the little girl stayed very calm. Later, her physicians found out that she had a gene that made her pain threshold above average. She may have had increased amounts of dopamine in her frontal lobes, making her more tolerant to physical pain.
Dopamine is greatly involved in feelings of reward, alertness and purposeful behavior. Dopamine is commonly associated with the 'pleasure system' of the brain, providing feelings of enjoyment and reinforcement to motivate us to do, or continue doing certain activities. Dopamine is released by naturally rewarding experiences such as food, sex, the uses of certain drugs and stimuli that become associated with them. In milder disorders, too much dopamine in the limbic system (a network of brain structures) is associated with emotion and memory problems, and not enough in the cerebral cortex may produce an overly suspicious personality prone to bouts of paranoia that may inhibit social interaction.
Alcohol can increase dopamine levels in brain regions collectively called the mesolimbic system by curtailing the enzyme activity that breaks down dopamine. When alcoholics suddenly stop drinking alcohol, their dopamine levels plunge, causing dysphoria, an unpleasant feeling, and anhedonia, the inability to experience the pleasure from normally pleasurable events, such as eating, exercise and social interactions.
The sudden drop of dopamine might contribute to the intense ethanol craving experienced by addicts, explained by Weiss et al. in the Journal of Neuroscience 1996. These ethanol-induced changes in dopamine levels provide positive reinforcement that contributes to continued alcohol abuse. People that have stronger releases of dopamine when they drink alcohol or coffee tend to be addicted to alcohol, especially people who are very smart and do not enjoy social networks. Other people do not have enough enzyme to process alcohol, so they feel stomach pain, nausea, dizzy. A certain group of people will never be able to enjoy alcohol.
Acupuncture at the specific point Ht7 (at the ulnar end of the transverse crease of the wrist, in the depression on the radial side of the tendon of medial flexor carpi ulnaris), but not at control points PC6 (2 inches above transverse crease of wrist, between tendons of medial palmaris longus and medial flexor radialis) or tail, prevented both a decrease of dopamine levels in a specific brain region called the nucleus accumbens during ethanol withdrawal and an increase of dopamine levels induced by an ethanol challenge. Stimulation of Ht7 facilitates normalization of dopamine levels in the brain following chronic ethanol exposure. If people are trying to quit drinking, acupuncture 2 to 3 times a week can help their body stabilize their dopamine level so they do not get depressed or agitated.
Nicotine induces tolerance and addiction by acting on the central dopaminergic pathways (those using dopamine as a neurotransmitter), thus leading to pleasure and reward sensations. It stimulates the central nervous system, enhances alertness and reduces appetite. Many women are reluctant to quit smoking because they are afraid to gain weight. A 50% reduction of nicotine consumption may trigger withdrawal symptoms in addicted individuals including anxiety, anger, sleep disorders, hunger, cognitive dysfunction and cigarette cravings. Certain drugs that inhibit the reuptake of dopamine are used for quitting smoking. However, those drugs can be dangerous to people who have epilepsy, eating disorders, uncontrolled hypertension, recent alcohol abstinence, or are undergoing current therapy with mono-amine oxidase inhibitors (drugs increase norepinephrine and epinephrine levels).
If you have smoked for more than ten years, certain enzyme activities have changed. When you suddenly quit smoking, reduced dopamine levels will make you feel miserable. Ear and body acupuncture can help your body rebalance the brain chemicals, producing more feel-good hormones, such as dopamine, serotonin, and endorphin, and reducing stress hormones, such as adrenaline and cortisol. Acupuncture stimulates your own body to rebalance those complicated hormones instead of just inhibiting or stimulating the metabolism of specific hormones. It is hard to use just one chemical change to explain the response of the entire body.
One lady had smoked a pack of cigarettes per day for 30 years before she started acupuncture treatments. After her best friend died of lung cancer at the age of 50, she finally decided to quit. She had acupuncture twice a week for 6 weeks. Surprisingly, she did not have any withdrawal symptoms or even gain any weight. Another lady had a couple of ear needles for 3 months; she never went back to smoking. Her daughter said that she was extremely surprised because her mother had been a heavy smoker for more than 20 years. However, not everybody has successful stories. Two major factors affecting success are the extent of a person's determination to quit and the busyness of the person's schedule during the quitting process.
Morphine can also induce dopamine release, causing addiction. Acupuncture can suppress Morphine Withdrawal Syndrome. In 2005, Dr. Kim and his colleagues in South Korea reported results of a study on how acupuncture can change dopamine levels and influence behavior in rats sensitized to morphine. They posted their results in the magazine Neuroscience Letter. Acupuncture at the specific acupuncture point HT7, but not at control points (TW8 and tail), significantly decreased both dopamine release in the nucleus accumbens and behavioral hyperactivity induced by a systemic morphine challenge. These results suggest that the therapeutic effect of acupuncture on morphine addiction occurs through normalization of dopamine and reduction of behavioral sensitization by morphine.