Postsynaptic chemically controlled ion channels are a possible location for the action of anaesthetics. The nicotinic acetylcholine receptor (AcChoR) is a member of a superfamily of chemically controlled ion channels, which have a large number of structural similarities in common. This receptor provides an excellent model for studying the effects of anaesthetics on excitable membrane proteins since it is well characterised and available in large quantities. The AcChoR consists of five subunits that surround a central ion channel. Anaesthetics can inhibit the function of the AcChoR by several different mechanisms: 1. By directly blocking the ion channel, 2. by an allosteric inhibition of the ion channel, 3. by changing the properties of the cell membrane surrounding the receptor. In high concentrations, anaesthetics stabilize the receptor in a desensitized state. Investigation of the mode of action of anaesthetics on the AcChoR provides important information as to the mechanisms of anaesthesia.