Relation between isoflurane concentration and NNE as measured by IOSs.

<p>(A) Isoflurane bath concentrations during the experiments measured by gas chromatography (closed circles, solid lines) and isoflurane tissue concentrations modeled via Fick’s diffusion law (dotted lines) for the three different vapor settings (<i>A</i>, <i>B</i>, and <i>C</i>) used. Isoflurane has to enter the brain slice submerged in the recording chamber via diffusion, causing a delayed equilibration of bath and tissue concentrations. (B) Dose-response curves calculated using the isoflurane tissue concentrations from (A) and the measured IOS intensities depicted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039346#pone-0039346-g003" target="_blank">Figure 3</a>. 0.1 mM isoflurane increases the IOS in the CA1 region of the hippocampus, while it decreases it in neocortical layer 5 (L5) at the same time. Isoflurane concentrations >0.3 mM considerably reduce the IOS in CA1 as well as in the neocortex.