Tim Little wrote:
 > To me they look like the sort of photocopied "secret government
 > material" that anti-government groups might pass around between each
other.

Yes, yes, a thousand times yes. I should have been more clear in my
initial post - they have the appearance (format) but not the substance
(content) of official material.

Leonard Erickson wrote:
 > There are surgical meds that have this effect. They paralyze the
 > voluntary muscles but don't affect the heart or lungs.

They affect the heart and lungs indirectly to a potentially lethal degree.

As Ken Barns goes on to point out, your respiratory muscles (e.g.
diaphragm, intercostals) are striated ones just as the same as other
skeletal muscle that can be controlled voluntarily.

Volatile anaesthetic gases can depress skeletal muscle function to the
point of flaccid paralysis if you give enough. Usually cardiovascular
collapse happens around the same time.

Derivatives were investigated as 'immobilising agents' but the ratio of
lethal to effective dose is not very high...

The purpose made neuromuscular blocking drugs (curare derivatives,
aminosteroids, succinylcholine) can only be given by injection.

 > Apparently the gas worked it's way up the spine. So at first you'd
 > lose control of toes, then ankles, lower leg, upper leg, etc.

This pattern doesn't fit with pharmacological neuromuscular blockade
where active muscles get blocked first.

Ascending paralysis of this sort is the classical presentation of
demyelinating diseases like Guillain-Barre syndrome.

Acutely interrupting the transmission of nerve impulses would require
very large doses of sodium channel blockers that would lead to seizures
and cardiac arrest in short order (the channel proteins are same in the
various tissues).

 > So if you make it a gas rather than an "EMP" bomb, it'd be doable.

Only if you are prepared to kill a good proportion of those exposed,
given current understanding of the relevant physiology and pharmacology.

The fentanyl derivatives used by Russian security forces in the Moscow
theatre siege in 2002 are illustrative.

Highly lipid soluble, so taken up into the bloodstream easily by
inhalation. Extremely narrow therapeutic index, so death by central
respiratory depression (suppressing medullary respiratory centre) was
the result for too many of the victims.

Rob O'Connor