Theories of General Anaesthetic Action

Theories Of General Anaesthetic Action

A general anaesthetic (or anesthetic) is a drug that brings about a reversible loss of consciousness. These drugs are generally administered by an anaesthetist/anaesthesiologist in order to induce or maintain general anaesthesia to facilitate surgery.

General anaesthetics have been widely used in surgery since 1842 when Crawford Long for the first time administered diethyl ether to a patient and performed a painless operation. It has always been believed that general anaesthetics exert their effects (analgesia, amnesia, immobility) by modulating the activity of membrane proteins in the neuronal membrane. However, the exact location and mechanism of this action are still largely unknown although much research has been done in this area. There are a number of outdated and modern theories that attempt to explain anaesthetic action.

The concept of specific interactions between receptors and drugs first introduced by Paul Ehrlich states that drugs act only when they are bound to their targets (receptors). However, this concept is not working well in case of general anaesthetics because:

  • Molecular structures of general anaesthetics widely used in medicine are very simple and diverse so that there is no obvious structure–activity relationship (see structures of general anaesthetics widely used in medicine: 1-ethanol, 2- chloroform, 3-diethylether, 4-fluroxene, 5-halothane, 6-metheoxyflurane, 7- enflurane, 8-isoflurane, 9-desflurane, 10-sevoflurane)
  • Most general anaesthetics have remarkably weak affinity for their targets acting at much higher concentrations than most other drugs so that diverse side effects are inevitable .

All these common features of general anaesthetics made it hard for early researchers to believe that general anaesthetics act in a specific manner and their action on neuronal membrane was thought to be global (through nonspecific perturbation of lipid membrane of CNS neurons) rather than through specific sites.

Read more about Theories Of General Anaesthetic Action:  Lipid Solubility-anaesthetic Potency Correlation (the Meyer-Overton Correlation), Outdated Lipid Hypotheses of General Anaesthetic Action, Modern Lipid Hypothesis, Membrane Protein Hypothesis of General Anaesthetic Action

Other articles related to "theories of general anaesthetic action, anaesthetic, general":

Theories Of General Anaesthetic Action - Membrane Protein Hypothesis of General Anaesthetic Action
... They found that two classes of proteins are inactivated by clinical doses of anaesthetic in the total absence of lipid ... Remarkably, inhibition of these proteins by general anaesthetics was directly correlated with their anaesthetic potencies ... cutoff, which is related to the size of the anaesthetic-binding pocket ...

Famous quotes containing the words theories of, action, general and/or theories:

    Theories of child development and guidelines for parents are not cast in stone. They are constantly changing and adapting to new information and new pressures. There is no “right” way, just as there are no magic incantations that will always painlessly resolve a child’s problems.
    Lawrence Kutner (20th century)

    Statecraft is soulcraft. Just as all education is moral education because learning conditions conduct, much legislation is moral legislation because it conditions the action and the thought of the nation in broad and important spheres of life.
    George F. Will (b. 1941)

    In general I do not draw well with literary men—not that I dislike them but I never know what to say to them after I have praised their last publication.
    George Gordon Noel Byron (1788–1824)

    In the course of a life devoted less to living than to reading, I have verified many times that literary intentions and theories are nothing more than stimuli and that the final work usually ignores or even contradicts them.
    Jorge Luis Borges (1899–1986)