Dopamine antagonists are chemicals that occupy dopamine receptors without stimulating them. They thus compete with dopamine for its natural binding sites and hence lower the effects of available dopamine. This can have the same neurological effects as actually lowering the brain's levels of dopamine. As dopamine stimulates motivation, reward and attention to detail, extreme dopamine activity can result in addictive or psychotic behavior. Dopamine antagonists can down-regulate this behavior.
Decrease Addiction and Weakness of Will
Dopamine antagonists have traditionally been used in controlling substance addiction, which is generally associated with high levels of dopamine that create a pleasurable feeling in response to pleasurable activities and make people want to repeat the activities. Dopamine also makes people seek instant gratification over long-term rewards, reports a research team in the June 2010 issue of Journal of Neuroscience. The researchers looked at decision making in 14 participants who were given either L-dopa, which increases dopamine levels, or a placebo. They found that participants who were given L-dopa were more likely to choose instant gratification than individuals who were given the placebo. Dopamine antagonists may thus help individuals with heightened levels of dopamine overcome their weakness of will.
Reduce Schizophrenia Symptoms
Changes in the white matter of the brain is the main trigger of schizophrenia, according to a study published in the May 2007 issue of Proceedings of the National Academy of Sciences. White matter consists of the myelin-covered neuron projections that conduct signals away from neurons. Defects in the brain's white matter cause increases in dopamine production, the researchers found, and these increases in dopamine production may be responsible for the extreme attention to details in schizophrenia. Dopamine antagonists help to counteract this effect.
The behavior of schizophrenics is in some ways the opposite of the behavior of people with attention-deficit disorder. The latter group of individuals cannot pay attention for very long and tend to ride roughshod over detail. Schizophrenics and others with psychotic disorders appear to add too much weight to irrelevant details, which can lead to paranoia and hallucinatory experiences.
Quell Romantic Love and Obsession
Dopamine antagonists may also turn out to be helpful in treating certain kinds of obsessive behavior related to romantic rejection. The painful emotions people who have recently gone through a difficult breakup feel is linked to high dopamine levels, report a research team in the July 2010 issue of Journal of Neurophysiology. The researchers scanned the brains of individuals who were still "into" the other person after a breakup and found that the brains of these individuals were similar to the brains of people addicted to cocaine. The altered dopamine system in people suffering from painful breakups partially explains their tendency to engage in obsessive and addiction-like behavior. Dopamine antagonists help to revers this dopamine flood.
Reduce Tics and Tourette's Syndrome
Tourette's syndrome is a neurological disorder associated with a malfunction of the ventral striatum and caudate nucleus, two central areas of the basic ganglia of the brain, reports a research team in the August 2003 issue of Neurology. Tourette's syndrome gives rise to tics, other involuntary repetitive moments, obsession and compulsion. Only very occasionally does Tourette's lead to an involuntary exclamation of vulgar language. Dopamine antagonists have been successful in controlling tics, presumably by blocking dopamine receptors in the ventral striatum, the researchers note.
References
- "Journal of Neuroscience"; Dopamine, Time, and Impulsivity in Humans; Alex Pine, et al.; June 2010
- "Proceedings of the National Academy of Sciences"; Loss of ErbB Signaling in Oligodendrocytes Alters Myelin and Dopaminergic Function, A Potential Mechanism for Neuropsychiatric Disorders; Kristine Roy, et al.; May 2007
- "Journal of Neurophysiology"; Reward, Addiction and Emotion Regulation Systems Associated with Rejection in Love; H. E. Fisher, et al.; July 2010
- "Neurology"; Increased Ventral Striatal Monoaminergic Innervation in Tourette Syndrome; R. L. Albin, et al.; August 2003
