Male mice in pain want sex, but females don’t

Male mice, for their part, were tested in an undivided chamber in which they had free access to a female partner in heat. Their sexual behavior was entirely unaffected by the same inflammatory pain. (Credit: "two mice" via Shutterstock)

Pain from inflammation greatly reduces sexual motivation in female mice in heat—but has no such effect on males, research shows.

“We know from other studies that women’s sexual desire is far more dependent on context than men’s—but whether this is due to biological or social/cultural factors, such as upbringing and media influence, isn’t known,” says Jeffrey Mogil, a psychology professor at McGill University.

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“Our finding that female mice, too, show pain-inhibited sexual desire suggests there may be an evolutionary biology explanation for these effects in humans—and not simply a sociocultural one.”

For a new study published in the Journal of Neuroscience, researchers placed mice in a mating chamber divided by a barrier with openings too small for male mice to squeeze through. This allowed the females to decide whether, and for how long, to spend time with a male partner.

Female mice in pain spent less time on the “male side” of the testing chamber, and as a result, engaged in less sexual behavior. The females’ sexual motivation could be revived, with a pain-relieving drug (pregabalin) or with either of two known desire-enhancing drugs.

Male mice, for their part, were tested in an undivided chamber in which they had free access to a female partner in heat. Their sexual behavior was entirely unaffected by the same inflammatory pain. There were no differences in pain perception between the two sexes.

Pain and sexual desire

“Chronic pain is very often accompanied by sexual problems in humans,” says Yitzchak Binik, professor of psychology. “This research provides an animal model of pain-inhibited sexual desire that will help scientists study this important symptom of chronic pain.”

Melissa Farmer, now a postdoctoral fellow at Northwestern University, led the study as a doctoral student under the supervision of Mogil and Binik.

“The sex differences in pain reactivity open new doors to understanding how sexual responses are organized in the brain,” says James Pfaus, a professor at Concordia University and a coauthor of the study.

“In fact, the growing trend towards personalized medicine requires us to understand how particular ailments, along with their treatments, might impact the sexual lives of women and men.”

The US National Institutes of Health, the Louise and Alan Edwards Foundation, and Pfizer Canada Inc. supported the study.

Source: McGill University