There are a few things that are said to "relax and widen blood vessels"
1) The nitric oxide creators, nitroglycerine and sildenafil (as you point out).
2) ACE inhibitors (the main high blood pressure med, which "blocks angiotensin II" formation, among other things)
3) Statins (either by "smoothing" endothelial cells and/or increased NO production?)
Bodybuilders (and now elderlies that want more muscle mass) are also interested in these things, but it would be nice to know:
a) How do these 3 interact? (Is "blood pressure too low" a risk factor?, Are too-many old men w strong hearts and erections a threat to society?)
b) There are no warnings out about those taking statins, ACE inhibitors, Sildenafil simultaneously (did I just profile the typical old-guy?)
c) Typical wisdom of "if a little is good, then a lot is better" may be risky with all this?
d) Whoa!, there's surely a lot more to "relaxes and widens blood vessels" scientifically, but my reading implies that there is much more to be learned about all this? Like antibiotics and other medical interventions, they work but we don't entirely know how?
e) I guess that's partly the point of your article, the serendipitous discovery of nitroglycerin as a heart med.
My article wondering why Sildenafil isn't prescribed for broader medical usage:
