Differential actions of isoflurane, sevoflurane and thiopental on recurrent inhibitory interneurons in rat hippocampal slices

Though general anesthetics have a lot of targets to act on, it hasn't been certain what is main target of them. In the present study we have investigated the effects of isoflurane, sevoflurane and thiopental on recurrent inhibitory pathway of rat hippocampal CA1 area using extracellular recording techniques. Volatile anesthetics (isoflurane and sevoflurane) obviously reduced the PS amplitudes elicited with glutamine-mediated orthodromic stimuli alone and had no significant effect on GABA-mediated recurrent inhibition produced with alveus stimulation. On the other hand, thiopental had an obviously effect on recurrent inhibitory pathway, but not on orthodromic pathway. These results indicated that volatile anesthetics mainly act on glutamine-mediated orthodromic pathway, whereas thiopental only acts on GABA-mediated recurrent inhibitory pathway in this area. The mechanisms of general anesthetics could be agent-and pathway-specific.