theories about the mechanism of general anaesthesia

Last reviewed 01/2018

A diverse range of molecular structures can produce reversible depression of the central nervous system. It is unlikely that there is one unifying mechanism by which they all act.

One theory is that the mechanism is purely physico-chemical. The potency of a wide range of anaesthetics correlates well with their solubility in oil and lipids. Hence, it is suggested that these molecules could dissolve in the lipid bilayers of excitable cells such as neurones, increasing membrane fluidity and disrupting transmembrane ionic fluxes.

Alternatively, general anaesthetics may bind to a particular portion of cellular proteins. These could be membrane pores or active transporters involved in maintenance of the membrane potential, or intracellular enzymes.

There is also no single location for the action of general anaesthetics: synapses throughout the central nervous system are affected. Sites that have been variously purported to be crucial to anaesthesia include the brain stem, thalamus and cortex. This area of research has been advanced by the use of magnetic resonance imaging to visualise the alterations in metabolism with different agents.