FIGURE 8.

Effect of C₁₈-ceramide on mitochondrial respiration. Mitochondria were incubated as described under “Experimental Procedures” except that 2 mm Mg²⁺ was present from the beginning of the experiment. A, mitochondria were incubated with dodecane (trace 1) or 2 μm C₁₈-ceramide (trace 2) for 4 min followed by the addition of 200 μm ADP at 4 and 8 min. The numbers on the plot show respiratory rate expressed in nmol of O₂/min/mg of protein. The results are typical representative of three independent experiments. B, the plot of the respiratory rate data obtained in experiments similar to one shown in A. The results represent the average ± S.D. of three independent experiments. A two-taled Student's t test was performed, and the asterisk denotes value significantly different from the values obtained with untreated mitochondria (p < 0.05).