Effects of propofol on unitary inhibitory postsynaptic currents (uIPSCs) recorded from fast-spiking cell (FS)→pyramidal cell (Pyr)/FS/non-FS connections. (A) A schematic of an FS→Pyr connection with repetitive spike-firing properties of each neuron. Resting membrane potentials are shown on the left of the traces. (B) Effects of 10 μM of propofol on uIPSCs of the FS→Pyr connection. Presynaptic action currents in FS induced uIPSCs in Pyr. Propofol enhanced uIPSCs. Ten consecutive traces are shown in gray lines, and their average is shown in black. (C) Superimposed uIPSC traces in B. Traces during control conditions and propofol application are shown as thin and thick lines, respectively. (D) Time courses of the uIPSC amplitude, 80 to 20% decay time, and charge transfer before, during, and after propofol application in the FS→Pyr connection shown in A–C. (E) A dose–response curve of propofol-induced enhancement of uIPSC charge transfer in FS→Pyr connections. The data were fitted by logistic function. The number of cell pairs was shown in the parentheses. (F, G) Effects of 10 μM of propofol on uIPSCs obtained from FS→FS (F) and FS→non-FS connections (G). Note the enhancement of uIPSCs in both connections.