DISSECTING PENTOBARBITAL ACTIONS ON SINGLE VOLTAGE-GATED SODIUM-CHANNELS

In order to begin separating the roles of membrane protein structure a nd membrane protein milieu in anaesthetic interactions a new planar li pid bilayer technology is being used. Membrane proteins such as sodium channels from diverse tissue sources are inserted into identical lipi d and aqueous environments where they can be examined and compared ele ctrophysiologically in great detail. The results obtained with pentoba rbitone suggest that some anaesthetic interactions may be general and conserved, while other anaesthetic interactions may depend on the part icular sodium channel isoform. Furthermore, the alteration of the memb rane lipid composition can modulate anaesthetic effects. These results suggest that some cells may be more sensitive to anaesthetics than si milar cells in other tissues which express a different sodium channel type or a different membrane environment. Therefore, caution must be e xercised when generalizing findings concerning anaesthetic interaction s with channels from one tissue or cell type to all other channel isof orms.