Fig. 3.

Rate of CO₂ production in mice after breathing 15 min of H₂S or volatile general anesthetics. A, each gas significantly decreased CO₂ production, in a concentration-dependent manner, compared with control. ••, p < 0.01 and •••, p < 0.001 significance from H₂S at 80 ppm. ★, p < 0.05, ★★, p < 0.01, and ★★★, p < 0.001 significance from H₂S at 250 ppm. In terms of CO₂ production, H₂S at 80 ppm was essentially equivalent to 0.3% isoflurane, 0.5% halothane, and 1.0% sevoflurane; and H₂S at 250 ppm was equivalent to 0.9% isoflurane, 0.9% halothane, and 2.0% sevoflurane. B, the addition of H₂S at 80 ppm reduced (antagonized) the metabolic effect of each concentration of isoflurane (Iso). ★, p < 0.05; ★★, p < 0.01. Statistical analyses for both metabolic studies were performed by using one-way ANOVA with Bonferroni multiple comparison test.