Brain Chemical Could Spur Lovesickness

Oct. 16 -- WEDNESDAY, Oct. 15 (HealthDay News) -- Pity the lovelorn prairie vole. A new study finds that when this monogamous rodent is separated from a mate, its brain starts a process that ends in lovesickness.

The same mechanism might drive the feelings humans get when parted from a longtime mate, scientists say.

And it could also keep couples together -- even when it's not good for them.

"We all know of people who are in a long-term relationship where you can't imagine why they are together. It may be that we are getting glimpses of real brain mechanisms that are causing that," said study senior author Larry Young, a psychiatry professor at Emory University's Center for Behavioral Neuroscience, in Atlanta.

He and his colleagues published their findings Oct. 15 in the journal Neuropsychopharmacology.

It's not a stretch to compare the love life of the prairie vole to that of humans, say scientists who study the neuroscience of human coupling. The female vole lives less than two years and gives birth once every 21 days, but she spends her entire life with the same male. This kind of monogamy is rare in the animal kingdom, Young added.

"But in some species, there is something else that happens -- a bond forms between the two that can last one season or multiple seasons," he said. "It's not just about sex, it's about the relationship between the two."

So, the prairie vole has long been a relied-upon animal model for human coupling, which tends toward monogamy. In September, for example, researchers in Sweden announced they had found a "bonding gene" that seemed to encourage men to stay faithful. That work stemmed from previous studies conducted with male prairie voles.

In this latest work, Young and his group examined the brains of a variety of adult male voles. Some of the voles had lifelong female partners, while other hadn't had time to form such bonds and were best acquainted with brother or sister voles.

All of the voles were subjected to brief stress tests, such as a swimming challenge, or being placed in a maze.