Naked Pleasure

Researchers analyze oxytocin levels in naked mole rats to better understand their unique social behavior.
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They're anything but warm and fuzzy. Wrinkled, bald with slits for eyes, naked mole rats huddle together underground for warmth. While they have no hair, poor eyesight, an unregulated body temperature and no pain sensation in their skin, these critters have something that most rats, most mammals in fact, don't — a remarkable, eusocial, home life.

Like ants and some bees, naked mole rats belong to a cooperative colony with one queen, a few breeding males and many "undifferentiated" baby sitters/home keepers. New research shows that oxytocin (the "love" hormone) may contribute to their unique social situation.

Interested in how neurobiology relates to complex social structure, Nancy Forger, at the University of Massachusetts, Amherst, led a project to investigate the distribution of oxytocin in the brains of the baby sitters (I mean the non-breeding subordinates).

Oxytocin, a hormone produced in the brain (and some other tissues too) plays a role in social behavior, including pair bonding, sexual demeanor and nurturing. The finding that most intrigued the team was a heavy oxytocin signal in a region of the brain involved with pleasure, the nucleus accumbens. Located toward the front of the brain, the nucleus accumbens has been implicated in reward, motivation and addiction. Interestingly, similar data exists for the monogamous prairie vole, but for no other rodents species studied.

Overall, the distribution of oxytocin was consistent with other rodent types and similar between the male/female non-breeders. Future studies to compare the non-breeders to the queen or breeding males, however, will yield insights as to whether the nucleus accumbens/oxytocin consortium is unique to the naked mole rats or is specifically associated with pup care.

It would have been nice to see a direct comparison to the guinea pig rather than the mouse. While the naked mole rat is a rodent, it is neither a mole nor a rat and is more closely related to the porcupine or guinea pig than the mouse. Regardless, I suspect that the cold naked mole rats (which incidentally also feed feces to their young — wow) is having a good time.

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