Figure 4-11 Examples of unitary acetylcholine receptor channel currents before, during, and after local microperfusion with 5 mM isoflurane. Channel openings are represented by downward directions of the current trace. When isoflurane is removed (bottom panel), the channels are indistinguishable from those observed under control conditions. Notice that pre-equilibrated and 10-fold lower concentrations of isoflurane also decrease the average open duration of acetylcholine receptor channel currents.^[113] (From Brett RS, Dilger JP, Yland KF: Isoflurane causes "flickering" of the acetylcholine receptor channel: Observations using the patch clamp. Anesthesiology 69:161, 1988.)