BBC Horizon - Sexual Chemistry (1998)

Sexual Chemistry



Science Documentary hosted by Juliet Stevenson and published by BBC broadcasted as part of BBC Horizon series in 1998 -

English narration



Information



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Sexual Chemistry



The drug Viagra revolutionised the treatment of sexual dysfunction in men on its launch five years ago. An accidental

discovery, the tablet that gave impotent men the chance once more to have natural erections became the fastest selling

pill in history and has earned its manufacturer, Pfizer, over $6bn.



The search is now on for a similar drug that could help women. Research is revealing that female sexuality is more

complex than expected. For women suffering from a loss of desire many scientists believe that drugs acting on the brain

may be the way forward. A pioneering Scottish study may have identified just such a drug and begun testing it

scientifically.



1) A man thing



An erection is achieved by filling the erectile tissue of the penis with blood. Blood vessels widen to allow blood in

and then constrict to maintain the pressure. Male impotence was long thought to be a psychiatric effect, a result of

stress, anxiety or depression. Medical advice was that there was not much to be done. Some patients refused to take this

message on board.



Geddings Osbon used his profession (working in a tyre workshop in Georgia, USA) as inspiration for one solution.

Suffering from impotence himself, he designed a vacuum pump to create an erection by engorging his penis with blood and

containing it with a rubber band. Despite its problems of discomfort, his vacuum device achieved popularity and is still

recommended by medics to some men with erectile dysfunction.



The next leap forward came in 1983 when British urologist, Giles Brindley, gave an eye-opening presentation to

colleagues in the field, gathered at Las Vegas. He told them he had just injected himself with phenoxybenzamine and then

showed them the results, by dropping his trousers and displaying his erect organ.



Brindley had proved that a drug could be used to treat erection problems. Modern science accepts that impotence can be

the result of a number of medical conditions: high blood pressure, furred arteries and some types of diabetes. Injecting

phenoxybenzamine is relatively easy but an instant erection hardly fits into most people's natural sexual practice. A

pill would still be ideal.



2) Blues for the boys



In 1985, the drug company Pfizer was working on treatments for the heart complaint, angina. Dr Ian Osterloh and Dr Gill

Samuels were using sildenafil citrate to relax blood vessels, in the hope of easing the pain of narrowed cardiac

arteries. They were about to become unwitting sexual pioneers. Their drug did significantly increase blood flow, but not

in the heart. It did so in the penis.



With its side effect recognised, studies began to assess the compound's ability to treat impotence. Researchers in

Bristol assembled a library of explicit films in order to provide a controlled method of arousing the subjects. They

thought the blue tablets wouldn't cause an erection on their own, but could help lust to run its natural course.



The investigation pieced together how the compound - Viagra - was beating male impotence. When sexually excited, cells

in the penis produce a chemical messenger known as cyclic GMP. Its effect is to allow more blood to enter the erectile

tissue, making it more rigid. The level of cyclic GMP is continuously kept in check by an enzyme. Viagra acts to inhibit

the enzyme, preserving cyclic GMP and enabling the man to achieve an erection at a time that fits into having sex.



3) Viagra for women



With an understanding of the chemical mechanism that allows Viagra to intervene in the physical process of male

erections, it was natural for scientists to wonder what effect the drug would have for women. Female sexual problems

were a field that had received far less attention than males'. Like in men, it was supposed to be primarily a

psychological complaint.



Research showed that arousal chemicals in men and women are the same and also that the physiological similarities

between the penis and clitoris are greater than many realised. However, a number of studies have revealed that for the

vast majority of women with sexual problems, Viagra is little help. (Women with pelvic blood flow problems and some

spinal injuries can benefit.)



4) More intelligent sex



The reason it seems is that for women, being turned on sexually is more to do with the brain than the pelvis. Dr Ellen

Laan turned to erotic videos to try to understand the female sexual response. She showed women two films. One

concentrated on the man's pleasure; one on the woman's. Her subjects experienced increased vaginal blood flow with both

films, but only reported being turned on by the film that was more focussed on female pleasure. Laan deduced that -

unlike men - for women the genitals are not the best indicator of arousal.



The most common complaint of women who seek help for sexual problems is not a physical one but a loss of desire. Using

the contraceptive pill or anti-depressants can prompt it, as can childbirth, the menopause or falling out of love.

Sometimes it seems there is no reason. Finding a cure is much harder than helping men to bolster their equipment.



5) Sex on the brain



A Scottish nurse could yet become the pioneer for a drug treatment for women. Ian Russell specialises in helping people

with sexual problems. In 2001, he started giving a new drug product - apomorphine hydrochloride - to men with

impotence.



Apomorphine (licensed for men as Uprima and Ixense) is a drug designed to work in the brain itself. It mimics the brain

signalling chemical, dopamine, and has been shown to act in the hypothalamus, an area known to control physical arousal.

In men, apomorphine amplifies the signal to have an erection. But Ian Russell's trial participants reported that taking

the drug regularly did more than overcome impotence; it raised their levels of desire.



This unexpected discovery made Russell realise the drug could be useful for his female patients as well. He approached

Prof Jeremy Heaton from Ontario, Canada, who had developed apomorphine. Jeremy gave him the encouragement he needed to

set up a small pilot study. He gave women varying doses of apomorphine for 18 weeks. Questionnaires at six week

intervals assessed any change in their sexual function.



Eight out of the ten women reported an increase in sexual desire and in their overall sexual satisfaction. Russell was

encouraged but well aware that one small uncontrolled study could yield unrepresentative results. He is now embarking on

a larger, double blind study.



Meanwhile, research on rats has shown that dopamine's role in the brain extends beyond the hypothalamus. It's known to

play a role in the limbic system, the part of the brain thought to control emotion. This could explain the connection

with desire.



Drugs that aim to tackle female sexual problems are still years away from being licensed. However, as the differences -

and similarities - between the sexes become clearer, the essence of male and female sexuality is opening up to

scientific investigation.



Screenshots



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Technical Specs



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* Video Codec: XVID



* Video Bitrate: 1061 kbps



* Video Resolution: 408x640 (height x

width)



* Video Aspect Ratio: 2x3 (1:1,57)



* Audio Codec: MPEG-1 Layer 3 (MP3)





* Audio BitRate: 80 kbps



* Audio Streams: 1



* RunTime Per Part: 48 min 32,76 s

(72819 Frames)



* Part Size: 399,43 MB



Links



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1) Related Documentaries



* Secrets of the Sexes



* Sex



* Human Instinct



2) ed2k Links



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