Dissecting pentobarbitone actions on single voltage-gated sodium channels.

In order to begin separating the roles of membrane protein structure and membrane protein milieu in anaesthetic interactions a new planar lipid bilayer technology is being used. Membrane proteins such as sodium channels from diverse tissue sources are inserted into identical lipid and aqueous environments where they can be examined and compared electrophysiologically in great detail. The results obtained with pentobarbitone suggest that some anaesthetic interactions may be general and conserved, while other anaesthetic interactions may depend on the particular sodium channel isoform. Furthermore, the alteration of the membrane lipid composition can modulate anaesthetic effects. These results suggest that some cells may be more sensitive to anaesthetics than similar cells in other tissues which express a different sodium channel type or a different membrane environment. Therefore, caution must be exercised when generalizing findings concerning anaesthetic interactions with channels from one tissue or cell type to all other channel isoforms.