The hormone oxytocin is also known as the "love hormone" because of its effects on emotions. Now, researchers unraveled how the hormone possibly influences women's sexual interest in men.
In the new study "Oxytocin Modulates Female Sociosexual Behavior through a Specific Class of Prefrontal Cortical Interneurons," which was published in the journal Cell on Oct. 9, Miho Nakajima, from the Howard Hughes Medical Institute at The Rockefeller University, and colleagues conducted an experiment with mice to see what would happen if a group of oxytocin-responsive neurons found in the medial prefrontal cortex, an area of the brain associated with triggering behavior in mammals, is disrupted.
They found that the female mice whose oxytocin-responsive neurons were altered were no longer interested in male mice during estrus, the period when these animals are sexually receptive. The genetically modified mice, in fact, spent almost the same amount of time with male mice and a block of Lego during this period.
"Silencing of OxtrINs in the medial prefrontal cortex (mPFC) of female mice resulted in loss of social interest in male mice specifically during the sexually receptive phase of the estrous cycle," the researchers wrote.
Interestingly, the social interest of females towards other female mice during estrus was not changed. The genetically altered female mice also retained their social interest in male mice when they are not in heat. The researchers likewise observed that the social behavior of the male mice was not altered when they silenced the same neurons.
Nakajima said that the hormone oxytocin may be possibly prompting female mice in estrus to be interested in probing potential mates and this suggests that social computation in female mice varies depending on the stage of their reproductive cycle.
The effects of oxytocin on humans is the same as with mice but it is not yet clear if the hormone also influences the human equivalent of the interaction in mice. Study author Nathaniel Heintz, also from The Rockefeller University, said that the circuits found in mice may also exist similarly in humans and other species so understanding these could provide a better understanding of the effects of oxytocin.
"Our work highlights the importance of the prefrontal cortex in social and sexual behaviors and suggests that this critical cell population may mediate other aspects of behavior in response to the elevated oxytocin levels that occur in a variety of different contexts," Heintz said.
