Actions of anesthetics on ligand-gated ion channels: role of receptor subunit composition.

Molecular cloning of cDNAs coding for ligand-gated ion channel subunits makes it possible to study the pharmacology of recombinant receptors with defined subunit compositions. Many laboratories have used these techniques recently to study actions of agents that produce general anesthesia. We review the effects of volatile and intravenous anesthetics on recombinant GABAA, glycine, AMPA, kainate, NMDA, and 5HT3 receptors. Evidence for and against specific ligand-gated ion channel subunits as targets responsible for anesthesia or the side effects of anesthetic agents is discussed for each type of receptor. Subunit specific actions of some of the agents suggest that construction and testing of certain chimeric receptor subunits may be useful for defining the amino acid sequences responsible for anesthetic actions.