HaCKeRz KrOnIcKLeZ 3/HaCKeRz_KrOnIcKLeZ.iso/drugs/n2o.action

Text File | 1996-05-06 | 5KB | 91 lines

In article <[e-mail]> [e-mail] (Keith Lewis) writes:
>I've seen the claim that N2O does not react chemically more than once on
>this network, yet nobody seems to be able to explain why it gives you a
>buzz.  This sounds a bit fishy to me.

According to _Introduction to Anesthesia_, Dripps, Eckenhoff, Vandam,
the action of inhalation anesthetics is still not totally understood, but
there are several theories and possible explanations:

"The basic principle that lipid solubility of anesthetics governs anesthetic
action remains viable.  Specifically, the narcotic action of a drug
correlates strongly with its solubility in biologic membranes.  Interactions
of anesthetics with biologic membranes cause expansion of the membrane.
Membrane expansion by a critical volume of 0.4 per cent results in
anesthesia.  Evidence is available to show that anesthetics selectively
combine with hydrophobic groups in biologic proteins, whether purified or
membrane-associated.  Perhaps these alterations in membrane structure affect
synaptic transmission in the brain, giving rise to anesthesia."
Another possible method is changes in membrane protein structure altering
ion flow.  Action on membranes in mitochondria and endoplasmic reticulum
might also be responsible.
The primary anesthetic action seems to be the synapse.  Anesthetics may
alter the binding of neurotransmitter to specific receptor proteins.
The section concludes that the mechanisms are not necessarily exclusive of
one another.  Multiple mechanisms may be responsible for anesthesia.

Ken Shirriff                [e-mail]

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A FEW WORDS ON METHOD OF ACTION...
    N20 is a weak anaesthetic gas that has been in use since the
late 18th century both in surgery and at parties.  It is also used in
the dairy industry as a mixing and foaming agent as it is non-flammable,
bacteriostatic (stops bacteria from growing) and leaves no taste or
odour on the food.
    N2O does not combine with haemoglobin, but is carried free in
the blood and excreted unchanged through the lungs. The risk of hypoxia
comes not from any interaction between N2O and O2 in the blood or brain,
but from simply not inhaling oxygen often enough. The vast majority of
deaths from N2O abuse have been through stupidity (tying a plastic bag
full of N2O round the head, letting off a tank in a airtight place, that
sort of thing). There have been a few cases of malignant
hyperthermia (raised body temperature),and this is considered a
potentially serious threat to those with the genetic requirement (check
out your family history - look for deaths during surgery, both minor and
major).
    There are 4 stages of general anaesthesia. The first is
drowsiness, confusion and analgesia. The second stage involves
excitement, euphoria, spontaneous muscle movements, hallucinations
(auditory and visual). The third stage is loss of consciousness, and the
fourth stage is heading into coma, where the patient stops breathing.
Anaesthetists generally aim for the upper levels of stage three, which
is why some people 'wake up' during the operation - they've drifted up
into stage two. From personal experience, I think that recreational use
of inhalational anaesthetics (N2O and ether) induce stage 2 and
sometimes stage 3, depending on the pattern of use.
    General Anaesthetics can give nausea and vomiting as a side
effect, the risk of this is increased if you have been drinking alcohol.
Not only is this a bit unpleasant but there is a risk of inhaling your
own vomit if you are a bit confused or temporarily unconscious.
    Reverse tolerance has been reported in the literature, and this
seems to be confirmed by my own personal experiences. Reverse tolerance
is getting more intense or prolonged feelings with the same or lower
quantities of a drug. Most psychoactive substances don't work this way,
I don't know why N2O does. As all traces of the gas are excreted from
the body within an hour after cessation of use, it's not due to fat
stores being reintroduced to the blood (as can happen with marijuana).

    Be very careful of home made N2O. In some states of the US,
there is a leaflet floating around with instructions on how to make your
own, but you are almost guaranteed to end up with a lungful of assorted
rubbish like NO2, H2NO3, and other yummy toxic things. REF: Annals of
Internal Medicine, Vol 96, 3,Mar 1982,pp333-334:Home made Nitrous Oxide:
No laughing matter.

    Nitrous oxide will dissolve out of blood into air filled spaces
eg the intestines, the middle ear. N2O in the gut will just give you a
gut pain, but if you have ever had middle ear disease, or damaged ear
drums, you could be in for permanent hearing loss. There are also some
cases of transient hearing loss, but I don't know much about this.

    There isn't very much in the medical literature about
recreational use of N2O, which is a different pattern to surgical use.
Next time I get a tank, I'll run a few tests and observations on my
friends just to see what's really happening.

                            Karen