Fig. 1. Time course of the effect of (A ) propofol and (B ) intralipid (the clinical vehicle of propofol) on ciliary beat frequency (CBF) in cultured rat tracheal epithelial cells. After the control period (−5 min–0 min), dimethyl sulfoxide (DMSO; final concentration, 0.1%; n = 11; closed circles), propofol (final concentration, 100 μm; n = 10; open circles), Dulbecco modified Eagle medium (DMEM; n = 11; closed triangles) or intralipid (final concentration, 0.05%; n = 5; open triangles) was added to the medium at time zero (arrow), and CBF was observed during the subsequent 25 min. Values are mean ± SD. There is a significant difference over time between propofol and DMSO (P < 0.0001), but not between intralipid and DMEM (P = 0.7336).