QUOTE (Sengir @ Jan 21 2010, 05:25 AM)

Alright, so the receptors are a bit further down...but if there are receptors for it, shouldn't there also be (theoretically) agonists which activate them?
That's only assuming that constipation is exactly the opposite of diarrhea. Which it isn't. They exist in a continuum, and not one that has both on each extreme. GI motility agents are finicky, and different things apply to different bodies. Again, it's not really a cost effective option to put into a capsule round with DMSO. Unlike, say, IV diuretics, which can be had fairly cheap. Or some very simple stuff that is deadlier and more annoying.
If you can just dump some Ex-Lax into a round, then it would be cheap. But IV drugs tend to be expensive.