Jeff,
I'll try to call you this weekend to BS. Lots of planning going on around my place.
I read the Colubrid salivary toxin stuff, too. I'll try to track down some of the papers.
Here's a quote from Dr. W. Wuster on another forum:
Basically, the point has been made here already - the vast majority of "colubrids" have a venom gland that secretes many of the major toxin families also found in vipers and elapids. The exception, with greatly reduced or non-existent venom glands are some of the specialised constrictors like rat snakes, gophers, etc. All the natricines certainly have them.
Obviously, the discovery of this doesn't change how dangerous or harmless they are, but it does put the occasional swollen hand from a garter snake bite into an evolutionary context: it's not due to toad poisons, saliva allergy or even toxic saliva, it's due to venom, inherited from the common ancestor of all advanced snakes.
So should we call these "colubrids" venomous? From an evolutionary standpoint yes, since they have the same toxin-secreting glands secreting the same toxin families as front-fanged snakes.
From an educational or medical point of view, calling them "venomous but harmless" would be the most truthful approach, but would probably send out the wrong message (although practically everyone in the world lives with multiple species of venomous-but-harmless animals around freely in their houses - spiders).
Hope this helps.
Cheers,
WW
He suggests above that the rat snakes, gopher snakes, and their relatives (tribe Lampropeltini) have reduced Duvernoy's Glands. Of course, I do agree that digestive enzymes (modified proteins) are present in many vertebrate salivas and could be causing a reaction. I've just always attributed king/milk/rat/gopher snake bites' itch to the mechanical damage.
Garter and water snakes (the Natricine tribe) have well developed Duvernoy's Glands, as do several other Colubrid tribes.
I'll dig for some primary literature and see what I can come up with for Lampropeltini.
-Cole