Mechanism of action of volatile anesthetics: effects of halothane on glutamate receptors in vitro.

(1) We have investigated the effect of halothane on glutamate receptor-mediated excitation in pyramidal cells and interneurons of the hippocampal CA1 area. (2) Halothane similarly inhibited non-NMDA and NMDA receptor-mediated excitatory postsynaptic currents in both cell types at low concentrations but preferentially blocked responses to exogenously applied AMPA at higher concentrations. (3) Synaptically but not directly evoked action potentials in interneurons were inhibited by halothane.