January 31, 2000 07:21am
Addicted to your mate? Maybe you're like a vole
Source: Future Watch
by: Randy Ringen
Can you become addicted to another of your kind? You can if you are a prairie vole, a small rodent living in the Western United States.
Recent research with voles has revealed that the same brain chemicals that contribute to drug addiction in humans are also associated with mating in the vole, enabling it to establish a long-term, sexually monogamous relationship with its mate.
Both male and female voles are fiercely monogamous and remain sexually faithful for life. Though it is not yet clear what causes male voles to remain true, biologists have determined that the hormone oxytocin is what creates the literal chemistry of romance in the brains of females.
Oxytocin is found in both males and female mammals. It is released by the pituitary gland during sexual intercourse, childbirth, and breast feeding, not only in female voles, but also in women.
To test whether oxytocin was what induced faithfulness in the female voles, scientists gave female voles drugs that blocked the release of the hormone in their brains during mating. As a result, the females were unable to establish strong bonds with males. However, when the researchers injected female voles with oxytocin, they were able to pair bond with the nearest males even without mating.
Other vole research has found that the neurotransmitter dopamine also has the same effect on the rodent's love life. Biologists found that like oxytocin, the amount of dopamine in the brain of the vole increases dramatically during sex, and remains at a high level hours afterwards.
When scientists injected drugs into female voles to block the dopamine in their brains during mating, the voles were unable to bond with their male partners. And injections of dopamine-like drugs into females caused them to pair off with males.
The similarities between how oxytocin and dopamine affect female voles suggest that oxytocin stimulates the production of dopamine. Dopamine is already known to be an important part of the brain chemistry of drug addiction. Addictive drugs -- like cocaine and nicotine -- stimulate the production of dopamine. Brains do not become physically dependent on drugs, but on dopamine and its pleasant sensations.
Human behavior is a bit more complicated than that of prairie voles, and how oxytocin affects human relationships is not yet well understood. Could it be that in the not too distant future, lovers will be able to find romance not in long, moonlight drives and candlelight dinners, but in a pill? Perhaps they'll breakup using a patch...