January 4, 2013
Dopamine Receptor Gene Variant Linked To Longevity And Healthy Ageing
Connie K. Ho for redOrbit.com — Your Universe Online
A study by brain researchers at the University of California, Irvine (UCI) recently found that a dopamine-receptor gene variant that is related to personality traits can also impact healthy aging. Their findings were published in the January 2 edition of The Journal of Neuroscience.
In the paper, the researchers described how the gene variant, known as DRD4 7R allele, is associated with both active personality traits and longer life expectancy. The experiment was completed by Robert Moyzis, a professor of biological chemistry at UCI, and Dr. Nora Volkow, a psychiatrist who manages the National Institute on Drug Abuse (NIDA) as well as conducts research at the Brookhaven National Laboratory (BNL).
The scientists used information from the so-called “90+Study,” a project affiliated with UCI´s Institute for Memory Impairments and Neurological Disorders.
“While the genetic variant may not directly influence longevity,” explained Moyzis in a prepared statement, “it is associated with personality traits that have been shown to be important for living a longer, healthier life. It´s been well documented that the more you´re involved with social and physical activities, the more likely you´ll live longer. It could be as simple as that.”
The DRD4 7R variant is a part of the dopamine system in the midbrain, a cluster of cells in the brain that assists in the exchange of signals between neurons. The dopamine system is also critical for attention as well as learning reward-driven behaviors.
The DRD4 7R allele causes a weakening of the dopamine signaling system, which in turn results in a greater reactivity of an individual to his or her environment. Moyzis and his team found that the genetic variant was present in significantly higher rates in people over the age of 90, and separate studies have independently corroborated these results by demonstrating that DRD4 7R is related to higher life expectancy in lab mice.
Researchers also believe that people who have this variant gene appear to be interested in activities that are socially, intellectually and physically stimulating. Past studies have found that both physical and mental activity is important for healthy aging, and could help limit neurodegenerative illnesses such as Alzheimer´s disease. However, attention-deficit/hyperactivity disorders along with addictive and risk-prone behaviors have also been connected to the variant.
For the recent study, the research team looked at genetic samples from 310 participants in the 90+ study. The study´s oldest participants showed a 66 percent increase in the number of people carrying the variant gene over the younger control group of 2,902 individuals ranging from seven to 45 years of age. They discovered that the variant was more likely to be present in people who spent a greater amount of time engaging in physical activity.
“It is clear that individuals with this gene variant are already more likely to be responding to the well-known medical adage to get more physical activity,” concluded Moyzis in a statement.
Additionally, the scientists at the Brookhaven National Laboratory found that mice that did not have the DRD4 7R variant had a 7 to 9.7 percent decline in lifespan compared to the mice that had the gene.
While the current study shows that the genetic variant can help increase longevity, the team of investigators believes that further studies are needed to gain a more precise understanding of the mechanism behind its benefits.