Basic concepts of ion channel physiology and anaesthetic drug effects.

Ion channels regulate a diversity of physiological functions such as neuronal signalling, cardiac excitability and immune cell response. All of these systems may be affected during the conduct of general as well as local anaesthesia. Thus, the investigation of anaesthetic action on ion channels has become the focus of an increasing number of laboratory studies. Consequently, the concepts of ion channel physiology are becoming important for understanding the scientific and pharmacological basis of clinical anaesthesia. This brief guide is intended to help in understanding the increasing number of studies concerned with the effects of anaesthetic agents on ionic currents. The generation of ionic currents requires a complex molecular interplay of ions, ion channel proteins and lipid membranes. Anaesthetic agents frequently exhibit more than a single effect on ion channel function. Their effects can be described by quantifying the pharmacological alteration of ion channel activation, conductance and inactivation. Many physiological functions are directly influenced by ion channels. Pharmacological action on ion channels is thus fundamental to effects as well as side-effects of anaesthetic agents. The alteration of ion channel function by anaesthetic agents consequently determines their clinical effects.