Sciencebase has a short article on a potential new aphrodisiac. It’s called PT-141, or bremelanotide, or Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (“PT-141” is the useful search term if you want to hit up PubMed), and it’s a melanocortin agonist that works directly on the brain. It can be delivered as a nasal spray. It works on men, promoting erections, and it also seems to be effective on women, increasing sexual appetite.
“A dose of PT-141 results, in most cases, in a stirring in the loins in as little as 15 minutes,” reports Julian Dibbell, “Women, according to one set of results, feel ‘genital warmth, tingling and throbbing’, not to mention ‘a strong desire to have sex’.”
Wow. Makes me want to run out and buy stock in Palatin Technologies, the manufacturer.
But the story bugs me, and I have to dash a little cold water on it all. I just have my doubts that it can work as well as they claim.
This is a compound that stimulates receptors in the brain, receptors that are associated with the regulation of various kinds of appetites. If they are that easy to manipulate, as the article suggests, then evolution would have ‘noticed’ long ago—we ooze odorants all the time, we produce melanocortin, I’d be very surprised if there were not selection for secretion of a substance that has that kind of effect on prospective mates. And to complement that, of course, there would be selection for an ability to resist that kind of chemical manipulation. It makes me very suspicious that this compound is being over-hyped.
That doesn’t mean it doesn’t work, of course. Lean in close to your lover sometime, and take a deep breath; oh, yeah, it works. Lots of subtle phenomena can elicit arousal, smells included, but also such things as novelty, language, security, and trust. A chemical signal like PT-141 can be a part of the stimulus, but you hygienically-challenged mouth-breathing dullards of the world should sit back down: giving a lady at a bar a snort of a melanocortin agonist isn’t going to override her revulsion.
Besides, I thought the most provocative and significant part of the story was buried near the end of the Observer article.
The funny thing is, it appears there’s a certain humanlike subjectiveness to the sex life of lab animals as well. When Jim Pfaus tested PT-141 on his female rats, he based his experimental design partly on the work of Raul Paredes, a fellow rat sexologist testing the effects of something more elusive: personal autonomy. That’s a tricky thing to measure, but it can be done. Paredes did it like this: first, he looked at rat couples living in standard, box-shaped cages and recorded the details of their sexual behaviour. Then, he altered the cages in only one particular: he divided them into two chambers with a clear wall broken only by one opening, too small for the males to get through but just right for the females. Architecturally it was a minor change, but what it did for the females was huge. It let them get away from the males whenever they chose to, and thereby made it entirely their choice whether to have sex. Paredes then observed the rats’ behaviour in this altered setting. Here’s what he found: the effects of giving a female rat greater personal control over her sex life are essentially the same as those of giving her PT-141. Autonomy, in other words, is as real an aphrodisiac as any substance known to science.
Unfortunately, freedom isn’t something that a pharmaceutical company can market and sell, and it’s not quite as easy to carry as a pocket inhaler. I have a dream, though, that someday everyone will realize that you can’t manipulate people into love and lust, and that autonomy and mutual trust are the sexiest part of a relationship.
I’m also thinking that there’s a lesson here that our neighbor state to the west could learn (new slogan: “South Dakota is not for lovers” or maybe “South Dakota: the anti-libido state”).