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- In article <1992Oct5.135942.23068@linus.mitre.org> lewis@aera8700.mitre.org (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 shirriff@sprite.Berkeley.EDU
-
- =============================================================================
-
- 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
-
-
-