Figure 2

Dynein mutation does not decrease global hypermetabolism but shifts energy metabolism of SOD1(G93A) mice towards carbohydrate use. A- Total (left panel) and resting (right panel) energy expenditure of wild type (+/+) and dynein mutant mice (Cra/+) bearing SOD1(G93A) transgene (SOD1m, black columns) or not (Wt, empty columns) *P < 0.05 versus Wt. Note that SOD1(G93A) mice are hypermetabolic and that the dynein mutant genotype has no effect on this hypermetabolism. N = 9 mice per group. B- Energy expenditure of the same mice than in A as a function of time. Mice bearing a Cra dynein mutation are denoted by empty symbols, and their corresponding controls by a filled symbol. Mice bearing a SOD1(G93A) (SOD1m) transgene are labeled by a squared symbol and their controls by a circle. Note that in the diurnal period, there are no differences between +/+ and Cra/+ mice but that the presence of a SOD1(G93A) transgene increases energy expenditure. On the contrary, during nocturnal activity period, the presence of either Cra/+ mutation or SOD1(G93A) transgene increases energy expenditure. N = 9 mice per group. C-D- Respiratory quotient of the same mice than in A. The four groups of mice are shown in two graphs for clarity reasons. Mice non transgenic for SOD1(G93A) (SOD1m) are shown in panel C (filled symbols, +/+; empty symbols, Cra/+). Mice transgenic for SOD1(G93A) are shown in panel D (filled symbols, +/+; empty symbols, Cra/+). Note that the presence of a dynein mutation increases respiratory quotient in otherwise wild type mice, and even more potently in SOD1(G93A) mice.