Fig. 4. Concentration- and time-dependent effects of propofol (PPF) on the membrane potential of macrophage mitochondria. Macrophages were exposed to 3, 30, and 300 μm PPF for 1, 6, and 24 h. Mitochondrial membrane potential was determined by the flow cytometric method. Each value is expressed as mean ± SD for n = 6. *Values were considered to be statistically different from the respective control when the P value was less than 0.05.