What triggers desire in women to pop 'female Viagra'

New York: In trying to understand how "female Viagra" will affect the brain of women users, researchers from the University of Wisconsin-Madison have found that when brain metabolism dipped in monkeys during tests, desire went up in them for popping "female Viagra".

The findings showed that the drug, called flibanserin, by altering metabolic brain activity prompts increased female behaviour responses to grooming (intimate, gentle touching from males) -- a discovery that "offers the first insight into how the drug may be working in the brains of women".

David Abbott, professor of obstetrics and gynaecology and associate scientist Alexander Converse studied the effects of the flibanserin drug in the common marmoset, a monkey for which pair bonding is instrumental to mating success and family life.

Marmosets and humans have similar hormonal signalling activity and mating behaviours, especially in response to sexual cues such as touch and scent.

"The female marmosets in our study provided effective, unparalleled, controlled models, allowing us to determine how flibanserin acts in the primate brain," Abbott explained.

After mapping the animals' brains with MRI scans, the team found that glucose metabolism declined in hypothalamus, a brain centre linked to intimate grooming and solicitation of sex in both marmosets and rodents.

The amount of metabolic decline correlated directly with an increase in grooming by a male partner.

In short, the bigger the metabolic dip in brain activity, more the grooming.

"Metabolism in the prefrontal cortex, a brain area involved in assessing events and deciding on actions, was also reduced in females receiving flibanserin," Abbott noted, adding that the amount of decline predicted increased mutual grooming.

The research by the Wisconsin group was funded by the pharmaceutical company Boehringer Ingelheim, which developed flibanserin till 2011 when Sprout Pharmaceuticals took over development of the drug. Sprout earned FDA approval for the drug earlier this year.

Inhibited sexual desire, known as hypoactive sexual desire disorder, affects women but no biological cause is known.

In people, it can make physical intimacy difficult or impossible.

"More research is needed on the underlying mechanisms of how this new drug works, so that the treatment and safety can be improved," Abbott added in a paper appeared in the Journal of Sexual Medicine.