Love rats point to female sex drugCaroline Ryan
BBC News Online health staff
Scientists are developing a drug which could boost female sexual desire. Tests in female rats are proving promising, showing "significantly enhanced" sexual behaviour.
Its developers believe it could be a more significant development in the treatment of sexual dysfunction than Viagra.
If human trials do prove successful, it could be on the market within three years.
The drug, PT141, is being developed by researchers at Concordia University, Montreal, Canada and Palatin Technologies - the company which is developing it.
PT141 seems to encourage the female rats to actively seek out the males for sex, which in turn heightens their sexual arousal.
The drug, which comes in the form of a nasal spray, has a virtually instantaneous effect.
The company is carrying out tests to see if the drug benefits women who have normal sexual function.
A study involving men with erectile dysfunction is also underway.
Experts in the UK stress research into the drug is still at a very early stage, but say it is hopeful. Currently, the only help available for women with sexual dysfunction problems is psychological or sexual therapy.
PromisingPT141 is a copy of a hormone which has an effect on the nervous system called alpha-melanocyte-stimulating hormone.
It has been established that melanocyte-receptors in the brain play a part in several behaviours including sexual arousal.
So stimulating these receptors using PT141 may stimulate sexual function.
A study of around 40 female rats showed a three- to five-fold increase in solicitations in rats who were given the drug compared to those which were not.
Jim Pfaus, professor of psychology at Concordia University, is carrying out the research into PT141's effects on female rats, and he told BBC News Online: "It could be bigger than Viagra."
"There's nothing in the arsenal now to treat female sexual dysfunction. That's one of the things that's really promising about this drug.
"If you have a woman in a loving relationship, but who just doesn't feel desire for sex, the question is why. What goes on to inhibit that?"
He said it could be that there was an interruption in the "chain of command" within the body which leads to desiring sex.
Potential benefitsThis drug may be able to "jump-start" the connection that has failed, and the brain may re-learn the normal arousal response.
He said: "It only affected solicitation. It didn't affect the ability to copulate or the rate of copulation."
Professor Pfaus accepts there is a long way to go before the potential benefits can be confirmed, but he said the history of research using male rats was encouraging.
"We know of a good correlation between male rats and male humans."
But he said it was not yet known if female rats and humans were as similar.
Further research will look at whether repeated use of the drug reduces its effectiveness.
Dr Annette Shadiack, director of biological research for Palatin, said: "This has the potential to really meet an unmet need.
She added that the research was aimed creating a treatment which could "return a woman to her natural function."
Lack of treatmentsDr Selim Cellek, a senior research fellow in sexual dysfunction at the Wolfson Institute for Biomedical Research at University College London, said of the PT141 research: "This is hopeful, it might work, but there needs to be more research.
"It's acting on the brain, and we don't know much about how female sexual behaviour is regulated in the brain."
Dr Cellek said there was currently no drug treatment available for female sexual dysfunction.
He added that the research into PT141 could help understanding of female sexual arousal: "If you don't know how the machine works, you can't fix it when it doesn't."
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