http://www.ncbi.nlm....pubmed/17971108
"CONCLUSIONS: Isolated nicotine can significantly attenuate physiological sexual arousal in healthy nonsmoking men."
Note that this is for one time acute exposure (and to pure nicotine not tobacco smoke). It's a typical technique for this genre of antismoking mercenary "science".
Lots of things which are beneficial in the long term for some function will tend to impair the very same function in the early, acute application/use. For example, say you wanted to test how do weights exercises affect muscle strength. And say, your sponsor who sells muscle enhancing pills, would like to see the main competition to their pills, plain old inexpensive weight lifting, discredited. You take some nerds who have never exercised with weights, or lift anything at all heavier than iPhone, split them into test and control group, then have the test group subjects hold 60 pound weight up in the air for 40 minutes steady. The control group subjects are left alone to wander in the labs. Then you test both groups for muscle strength (or on any other performance, physical, sexual or mental). The test group will be wiped out, in pains, with muscle cramps, dislocated joints, pulled tendons,... and will certainly show poorer performance on the subsequent tests (of any kind).
And voila, your sponsor is very happy with your "science" and you can expect further contracts for similar "science" from them and other muscle enhancing pill manufacturers. That's exactly what those "scientists" did to "prove" harm from tobacco smoke (typically sponsored by those financially benefiting from antismoking, such as pharmaceutical industry, health buraucracies, federal & local governments extorting smokers with astronomical taxes, along with array of other opportunistic parasites in media, "education'' & academia).
Note also that pure nicotine is quite different from tobaco leaf smoke -- an ancient medicine tuned to perfection over the eight thousand years of use by more than two billions of lifelong test subjects, each enjoying immediate, continuous, information rich feedback from each interaction. The key to tuning some substance or procedure for some function are the amount and quality of
feedback information evaluating the targeted function. By virtue of delivering its medicinal components straight into the arterial bloodstream, tobacco smoke provides instant, accurate feedback, allowing for proper attribution of any changes in the effects to the immediately preceeding changes in the composition of tobacco smoke (affected in turn by tobacco leaf mixes used, curing, additives, burning rate, pipe construction, paper, filters, way of smoking,...). In contrast, the substances taken in through digestive system, such as foods, beverages, medicinal plants, pharmaceuticals,... take typically several orders of magnitude longer to reach the target systems and manifest their effects, which not only quantitatively reduces the feedback information flow by orders of magnitude compared to that from tobacco smoke, but the information quality is lowered as well since any effects are much harder to attribute to specific minor change in the ingested substance (especially in non-controlled daily life environment where much of such tuning goes on). Therefore, tobacco smoke was tuned more finely for its beneficial effects than just about anything else, other than water and air, we take.
In particular, regarding the effects of tobacco smoke on sexual performance (which is affected, among others, by acute vascular effects, along with acute & long term endocrine, central & peripheral nervous systems effects, psychological effects), there is quite a bit of difference between pure nicotine and tobacco smoke, not just in composition but in delivery mechanics.
First, while pure nicotine is
vasoconstricting in acute use, its long term effects include
stimulation of angogenesis and
formation of capillary networks (these effects have resulted in
drugs for treating congestive heart disease), which is certainly a therapeutic effect for impotence caused by circulatory problems (which include congestive heart disease as its underlying cause).
Second, unlike the pure nicotine, the finely tuned natural medicine, tobacco smoke, already includes several components which counter even those acute vasoconstricting effects of nicotine -- the vasodilating nitric oxide (the active ingredient behind none other than Viagra) and the vital oxygenation & circulatory signaling molecule, the
low dose carbon monoxide.
Third, considering other, non-circulatory, anti-impotence supplements and drugs, such as CoQ10 (the chief
natural source of which is tobacco leaf), pregnenolone, DHEA, testosterone (long term use of tobacco smoke upregulates these hormones and
slows down their decline with aging),
MAO inhibitors including selegiline (as noted above, TS is a potent MAOI),... the tobacco smoke covers harmoniously most of their effects as well.
Fourth, even the the mechanics of just nicotine delivery is quite different between tobacco smoking and ingested (or skin absorbed) nicotine. Smoking is a cyclic activity, with several nested cycles (puffs, cigarettes, smoke breaks, daily cycles, weekends,...), all finely controlled and tuned for optimal delivery rate, medicinal component composition (.e.g. speed of burning, inhalation rate, packing density affect CO & NO levels) and timing, by the immediate feedbacks from the affected biochemical networks of the user. In contrast, the blunt device of ingested pharmaceutical nicotine, lacks any such instant feedbacks. For example, while you can easily overdose, even lethally, on pharmaceutical nicotine, you just can't do that with tobacco smoke (its warning feedbacks as you approach anywhere close to lethal overdose ~60mg, 3 packs, are so dramatic and so clear, so early, that no one can possibly do it). That's why I brought up this difference in the weight lifting analogy above, where natural, spontaneous weight lifting (analogous to cyclic, finely self-tuning smoking) is contrasted with the contrived "experiment" in which subjects are made to lift the weight and hold it steady in the air for half an hour (analogous to ingesting the full daily dose of pharma nicotine and then suffering whatever effects are coming down, with no way to tune it, time it or adjust it at all, once it is in).
Edited by nightlight, 21 September 2009 - 08:00 AM.