Narcosis
- Thread starter phmadeira
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
try DAN website: https://www.daneurope.org/eng/english_.htm
Dr Deco
Contributor
- Messages
- 2,384
- Reaction score
- 96
- # of dives
- I just don't log dives
Hello phmadeira :
Narcosis
Nitrogen narcosis is a gradual dulling the senses by the inert gas nitrogen in the breathing gas. This led to the replacement of nitrogen by helium. The effect is sometimes as being similar to alcohol; the effect starts roughly at 60 fsw and increases with depth. It was originally called the "rapture of the deep." It vanishes quickly upon ascent.
Reaction
Divers react differently to narcosis as they do to alcohol consumption. It can be variable from dive to dive and day to day, but it will always begin appear at some depth as you descend.
Inert Gas Narcosis
As a diver, you are probably referring to nitrogen narcosis. This is a subset of narcosis by inert gases and that a subset of narcosis by volatile compounds, usually organic. Inert gases produce many biological effects, narcosis being just one [1]. Anesthetic agents differ remarkably in their chemical, physical, and pharmacological properties, as well as greatly varying in molecular size, in chemically active groups. There are also differences in the combinations of physical interactions and chemical reactions in which they can participate. Potency is often related to lipid ( = fats and oils) solubility, the Overton-Meyer Hypothesis of solubility in nerve membranes. Meyer wrote:
While narcosis is compared to alcohol imbibing, it is not clear how similar the two are. "Martini's Law" is often invoked for comparison, but that does not prove a mechanistic link. [3] One current idea is that anesthetics participate in the formation of bubbles in channels or pores in nerve membranes. [4] This theory falls prey to problems experienced by earlier theories.
Many poposed mechanisms exist, but none can explain everything, for example, why optical isomers of chloralose have different anesthetic potencies but by definition equal physicochemical properties. A fascinating history is referenced below. [5] For those who enjoy history - and that certainly includes Dr D - this is fascinating.
No one knows how it works, even after 150 years!
Dr Deco :doctor:
References :read:
1. MR Powell. The Role of the Noble Gas Series in Molecular Pharmacology, In: A Guide to Molecular Pharmacology-Toxicology, Vol. II. Chapter 13. [R.M. Featherstone, ed.], Marcel Dekker, New York, (1973).
2. Meyer H. Welche eigenschaft der Anasthetica bedingt ihre Narkotische wirkung? Naunyn-Schmied Arch Exp Path Pharmakol 1899; 42:109-118.
3. Hobbs M. Subjective and behavioural responses to nitrogen narcosis and alcohol. Undersea Hyperb Med. 2008 May-Jun;35(3):175-84.
4. Roth R, Gillespie D, Nonner W, Eisenberg RE. Bubbles, gating, and anesthetics in ion channels. Biophys J. 2008 Jun;94(11):4282-98.
5. Matthew D. Krasowski, Contradicting a Unitary Theory of General Anesthetic
Action: a History of Three Compounds from 1901 to 2001. Bull. Anesth. History. 21, 1, 2003.
Narcosis
Nitrogen narcosis is a gradual dulling the senses by the inert gas nitrogen in the breathing gas. This led to the replacement of nitrogen by helium. The effect is sometimes as being similar to alcohol; the effect starts roughly at 60 fsw and increases with depth. It was originally called the "rapture of the deep." It vanishes quickly upon ascent.
Reaction
Divers react differently to narcosis as they do to alcohol consumption. It can be variable from dive to dive and day to day, but it will always begin appear at some depth as you descend.
Inert Gas Narcosis
As a diver, you are probably referring to nitrogen narcosis. This is a subset of narcosis by inert gases and that a subset of narcosis by volatile compounds, usually organic. Inert gases produce many biological effects, narcosis being just one [1]. Anesthetic agents differ remarkably in their chemical, physical, and pharmacological properties, as well as greatly varying in molecular size, in chemically active groups. There are also differences in the combinations of physical interactions and chemical reactions in which they can participate. Potency is often related to lipid ( = fats and oils) solubility, the Overton-Meyer Hypothesis of solubility in nerve membranes. Meyer wrote:
"The narcotizing substance enters in a loose physico-chemical combination with the vitally important lipoids of the cell, perhaps with the lecithin, and in so doing changes their normal relationship to the other cell constituents, through which an inhibition of the entire cell chemism results. "[2]
While narcosis is compared to alcohol imbibing, it is not clear how similar the two are. "Martini's Law" is often invoked for comparison, but that does not prove a mechanistic link. [3] One current idea is that anesthetics participate in the formation of bubbles in channels or pores in nerve membranes. [4] This theory falls prey to problems experienced by earlier theories.
Many poposed mechanisms exist, but none can explain everything, for example, why optical isomers of chloralose have different anesthetic potencies but by definition equal physicochemical properties. A fascinating history is referenced below. [5] For those who enjoy history - and that certainly includes Dr D - this is fascinating.
No one knows how it works, even after 150 years!
Dr Deco :doctor:
References :read:
1. MR Powell. The Role of the Noble Gas Series in Molecular Pharmacology, In: A Guide to Molecular Pharmacology-Toxicology, Vol. II. Chapter 13. [R.M. Featherstone, ed.], Marcel Dekker, New York, (1973).
2. Meyer H. Welche eigenschaft der Anasthetica bedingt ihre Narkotische wirkung? Naunyn-Schmied Arch Exp Path Pharmakol 1899; 42:109-118.
3. Hobbs M. Subjective and behavioural responses to nitrogen narcosis and alcohol. Undersea Hyperb Med. 2008 May-Jun;35(3):175-84.
4. Roth R, Gillespie D, Nonner W, Eisenberg RE. Bubbles, gating, and anesthetics in ion channels. Biophys J. 2008 Jun;94(11):4282-98.
5. Matthew D. Krasowski, Contradicting a Unitary Theory of General Anesthetic
Action: a History of Three Compounds from 1901 to 2001. Bull. Anesth. History. 21, 1, 2003.
Similar threads
