Category: Sex

Over on Digg, there’s news that the organ in the brain responsible for female sexual response has been found. As one might expect, there are lots of sexist comments posting very early and at an alarming rate from the members: Female Libido

The actual news item in question can be found here, written by my good friend at New Scientist, Andy Coghlan.

What a surprise! Medical researchers have discovered that women’s brains light up when they look at erotic images just as men’s brains do.

Researchers at Washington University School of Medicine in St. Louis measured brainwave activity of 264 women as they viewed a series of 55 colour slides that contained various scenes from water skiers to snarling dogs to partially-clad couples in sensual poses.

What they found may seem like a “no brainer.” When study volunteers viewed erotic pictures, their brains produced electrical responses that were stronger than those elicited by other material that was viewed, no matter how pleasant or disturbing the other material may have been. This difference in brainwave response emerged very quickly, suggesting that different neural circuits may be involved in the processing of erotic images.

“That surprised us,” says WUSTL’s Andrey Anokhin, “We believed both pleasant and disturbing images would evoke a rapid response, but erotic scenes always elicited the strongest response.”

As subjects looked at the slides, electrodes on their scalps measured changes in the brain’s electrical activity called event-related potentials (ERPs). The researchers learned that regardless of a picture’s content, the brain acts very quickly to classify the visual image. The ERPs begin firing in the brain’s cortex long before a person is conscious of whether they are seeing a picture that is pleasant, unpleasant or neutral.

Previous research has suggested that men are more stimulated by erotic images than women. Anokhin says the fact that the women’s brains in this study exhibited such a quick response to erotic pictures suggests that, perhaps for evolutionary reasons, our brains are programmed to preferentially respond to erotic material.

“Usually men subjectively rate erotic material much higher than women,” he says. “So based on those data we would expect lower responses in women, but that was not the case. Women have responses as strong as those seen in men.”

So when one sees statistics on net usage that reveal porn accounts for 80% of traffic, it might not just be males who are using up all that bandwidth? Really? Well, I never!

What’s most intriguing though, is that when one searches for the original news release on this item from WUSTL, the cached page in Google shows the context for the phrase “erotic images elicit” as being:

“Attention grabber Erotic images elicit strong response from brain … When study…”

Well, WUSTL press officer, it certainly grabbed my attention. The news release could have done with a few more pictures though!

The vexing question of whether sex pheromones play a role in human sexual attraction raises its ugly head once again, this time in a posting on The Register. Most scientists would say that there is little evidence that humans rely very much on pheromones for sexual attraction directly. However, others scientists suggest that a tiny organ in the nasal cavity, the so-called vomeronasal organ (VNO), or Jacobson’s organ, can detect chemical attractants that pass between people and are not apparent to us at the thinking level. Moreover, anecdotal evidence would point to smell having a very strong effect in sex whether or not we believe it’s pheromonal or not.

The VNO definitely plays a role in the lives of other animals from cats to snakes and from elephants to mice. In humans the organ seemingly all but disappears even before birth, leaving just a few people with a tiny pit in the septum that might have some vestige of pheromonal responsiveness.

Until, we find specific chemicals that trigger sexual attraction when sniffed, in double-blind controlled tests, it is likely that for the foreseeable future there will be no genuine, working product.

Readers interested in sexual chemistry will have spotted the recent item on bremelanotide (Sex Gets Up Women’s Noses, April 24, 2006), which is soon to enter Phase III clinical trials for female sexual dysfunction (see also PLoS Medicine on the subject of disease mongering).

Anyway, recent sciencebase visitors have been trying to locate the material data safety sheet (MSDS) for this compound (judging from the recent spate of searches on the site for that term). Anyway, ChemSpy.com has excellent access to several MSDS sources here. If it’s listed anywhere you should be able to find the bremelanotide MSDS there.

A blogger on another site discussing my short bremelanotide article, suggested that the fact this drug is odourless and colourless represented a serious risk in terms of men spiking a woman’s drink, but I wonder…this drug doesn’t knock you out or give you amnesia it just makes you horny, so if Mr B. Nomates can’t score under normal circumstances when any number of potential mates may be horny or not, it won’t seriously boost his chances will it?

Size really does matter! In fact a micro device that can analyse even the smallest of the small could help solve one of “man’s” greatest mysteries – what turns a sperm’s head and sends it in the direction of the egg for that fertilizatory encounter?

Sperm are well-known for turning their microscopic heads and changing direction (at least to those with a microscope who like to view such tiny events). Previous research (about which I wrote in 1991 under the heading “Not every sperm is sacred”) revealed that sperm turn in response to chemical signals, a process termed chemotaxis, and even have their own olfactory receptors. Such chemical messages may play key roles in the fertilization process. Defects in sperm chemotaxis may be a cause of infertility, and sperm chemotaxis could potentially be used as a diagnostic tool to determine sperm quality to treat male infertility.

However, Milos Novotny and Stephen Jacobson of Indiana University have developed a new tool to probe exactly how sperm chemotaxis occurs. In the current issue of Anal Chem, they describe the initial tests on their microfluidic device for studying sperm chemotaxis: “An advantage of the microfluidic platform over conventional chemotaxis assays is the ability to create chemical gradients with temporal and spatial stability, leading to greater repeatability in the experimental conditions.”

They add that microfluidic devices provide a convenient, disposable platform for conducting chemotaxis assays.

http://dx.doi.org/10.1021/ac052087i

Spray-on sex could usher in an age of McNookie, according to an article in The Observer on Sunday. PT-141 is billed as libido in an atomiser, says the paper, and could finally offer women the chance to turn on their sexual desire as and when they need it.

“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’.”

So, what is PT-141?

It’s an odourless and colourless synthetic chemical that you inhale deeply through a small, white plastic inhaler. The compound, produced by Palatin Technologies and currently undergoing regulatory assessment, is a melanocortin-based therapy that seems to work directly on the brain rather than simply stimulating the loins as is the case with Viagra.

The drug’s market name is Bremelanotide and it’s a word you’re sure to see a lot more of in the near future as spammers start offering it and variations on the theme (watch out for Bremelan0tide in your email subject lines). Its mode of action is poorly understood, but unlike thousands of years of rhino horn, tiger dick, and oysters this one definitely seems to work.

“It’s not merely allowing a sexual response to take place more easily,” Michael Perelman, co-director of the Human Sexuality Program at New York Presbyterian Hospital and a sexual-medicine adviser on the PT-141 trials explains, “It may be having an effect, literally, on how we think and feel.” What is known is that it acts on at least one of five known melanocortin receptor subtypes in the brain. These are chemical receptors that regulate a diverse array of functions including sexual arousal, appetite, energy maintenance and inflammation. The company is working on drugs to affect these receptors and so help with sexual dysfunction, obesity and cachexia (disease-related muscle loss).

One has to wonder though whether the advent of drugs like PT-141 is simply another example of the kind of drug mongering I discussed a few years ago my Alchemist column on ChemWeb. There now seem to be dozens more “diseases” than there ever were. Is it just coincidence that problems that were not considered problems are now categorised as syndromes and disorders have emerged at just the time when the patents are expiring on the billion dollar staples of the pharmaceutical industry? Maybe, maybe not. Some of those disorders, such as restless legs syndrome, may sound like spurious ailments invented by a desperate industry, but they certainly aren’t for those who suffer from them. Even shyness and anxiety might one day succumb to drugs, and why not? If these disorders are debilitating then who are we to suggest that sufferers have no right to a treatment that “cures” them?

Sometimes there is no relief for a whole range of problems without pharmaceutical intervention. Whether or not we should allow people the option to control their sexual desire chemically is a moot point, the fact is humans have used all kinds of methods to loosen up a libido for millennia, and will continue to do so whether that’s with a regulated drug or something else. Palatin seems simply to be hoping to take a slice out of the action.

Anyway, for those interested in such things Palatin gives the basic structure of its product as a short cyclic peptide with the sequence – Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH. It’s currently in Phase III clinical trials, so it shouldn’t be too long before those spams start arriving.

“Pour yourself a stiff one” Indeed! That’s the word on the pharma lecture circuit as drug companies work themselve up into a lather chasing liquid Viagra.. Meanwhile, there seems to be no end of new targets, even with malaria, cancer, TB, bird flu and the rest providing plenty of fodder, the pharma industry is intent on developing paying treatments for the likes of shyness, hypochondria, and of course premature ejaculation.

Dapoxetine was originally developed as a serotonin-reuptake inhibitor for depression. And, as male users of related quickly, or rather slowly, found out, these drugs cause retarded ejaculation. One man’s side-effect is another man’s therapy. Hence the repositioning, as it were, of Dapoxetine.

Anyway, the industry is, according to Alan Cassels writing in Canada’s CommonGround, keen to get into this new market, although the FDA deigned dapoxetine unapprovable saying that the manufacturer’s claims that it “�increased intra-vaginal ejaculatory latency (IEL) time” better than a placebo, did not stand up to closer examination. So, what will be the next big thing? Have you had enough of my puerile puns and blatant innuendos? Come again for more of the same!