Actions of anesthetics on excitatory transmitter-gated channels.

Excitatory transmitter-gated receptors are found in three gene families: the glutamate ionotropic receptors, the Cys-loop receptor family (nicotinic and 5HT3), and the purinergic (P2X) receptors. Anesthetic drugs act on many members of these families, but in most cases the effects are unlikely to be related to clinically relevant anesthetic actions. However, the gaseous anesthetics (xenon and nitrous oxide) and the dissociative anesthetics (ketamine) have significant inhibitory activity at one type of glutamate receptor (the NMDA receptor) that is likely to contribute to anesthetic action. It is possible that some actions at neuronal nicotinic receptors may make a smaller contribution to effects of some anesthetics.