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Sexual Desire May Be Revealed in Probe of Prairie Vole Genetics(Found in US) :

Prairie voles, the furry rodents found in tall-grass fields in the U.S. Midwest, may help scientists unlock age-old mysteries underlying human desire for companionship, sex and even the accumulation of wealth.

Research on the animal’s genetic makeup is uncovering more about human behavior than does the study of “just about any other species,” said Larry J. Young, a social-neurobiology researcher at Emory University in Atlanta. Voles have become the focus of scientists because they mate monogamously, unlike rats and monkeys. Voles also produce oxytocin, a hormone that spurs mothers to bond with babies, and dopamine, which fuels human cravings and euphoria.

Within months, Young and his colleagues will begin mapping the prairie vole’s genome after getting the animal approved for sequencing by the National Human Genome Research Institute in Bethesda, Maryland. The findings will advance understanding of the relationships between genes, the brain and behavior, and may lead to new therapies for autism and other social disorders, said Young, who has studied voles for 15 years.

“Dopamine is involved in all kinds of rewards, things that make us feel good: eating, drinking, winning a football game, making money, buying a new car,” Young said. “Oxytocin is that reward of being around friends, a mate. There are times when you have the combination of the two -- like when you are making love.”

Oxytocin in the form of pitocin is frequently given to mothers during or after childbirth to speed delivery and reduce hemorrhaging, and is being used experimentally to treat autism, said Sue Carter, a biologist and co-director of the Brain Body Center at the University of Illinois at Chicago, who has studied voles for three decades.

Vero Labs, Genesis

Companies are trying to capitalize on oxytocin’s role in bonding and trust. Vero Labs LLC in Boca Raton, Florida, sells an oxytocin spray it calls Liquid Trust, and Genesis Biolabs Inc. in Tucson, Arizona, markets a “ruthlessness/bonding” test kit for humans that looks for the AVPR1a receptor gene that is also involved in prairie vole social behavior.

Like voles, some people have a genetic tendency to be more social and introduce their friends to each other, while others tend to keep to themselves, said Nicholas Christakis, co-author of “Connected” (Little Brown, 2009), which explains why behaviors are contagious and why the rich keep getting richer.

“It’s a similar group of genes that influence pro-social behavior in prairie voles and us,” said Christakis, who also teaches health-care policy, sociology and medicine at Harvard Medical School in Boston. “There are advantages to these social networks. If you want to hunt a mastodon, it’s better to have your friends along.”

Sex Chemistry

The first time prairie voles mate, the chemistry of their brains is altered and they form a lasting bond with each other, even after they stop producing offspring, Young said. Some related species, such as meadow voles, aren’t monogamous, he said.

“There’s this flip-flopping of the neurochemistry in the brain that prevents them from forming that kind of bond again,” said Young, who organized a gathering of vole researchers in February that drew 90 attendees to Emory.

Although some prairie voles may later have sex with another partner to reproduce, the oxytocin-driven social bond won’t form again, said Young, who earned his Ph.D. in neuroendocrinology from the University of Texas at Austin.

Intimate Contact

“If someone wants to know the best way to keep a relationship going, it’s to engage in activities that stimulate oxytocin, that is, intimate contact,” Young said. “Your body is wired to be sensitive to the kind of intimate contact when you’re making love to release both oxytocin and dopamine to active those systems.”

There are now 25 labs in the U.S. that are doing vole research, and two in Japan, Young said.

Prairie voles have been a “particularly thrilling” research subject because their monogamy and bonding behavior is both uncommon among mammals and strikingly similar to that of humans, said Joseph Lonstein, a neuroscientist who helps run a lab with about 100 voles at Michigan State University in East Lansing.

“The same mechanism that causes us to desire sex or to gamble or to parent, those are the same structures involved in social bonding,” Lonstein said.

Alcohol-Drinking Voles

A 2007 study at the University of Illinois at Chicago found that social isolation leads to depression in prairie voles.

In an ongoing study at the Oregon Health and Science University, in Portland, voles consumed more alcohol when housed together than when isolated from their mates or relatives -- which researchers said may be a useful model for studying drinking behavior of humans.

Gene mapping will most likely lead to research on voles that may help scientists learn why the initial carnal attraction between humans evolves to a lasting social bond and how to improve social behavior, said Young, 42, who has five children and lives in Atlanta with his wife, Anne.

It may also yield clues on what drives our desires to make money.

“Dopamine and oxytocin, these are the ones we know of,” Young said. “In mapping the whole genome, we can see what these other things are” that also influence behavior.