Figure 3.

Differential effects of eicosanoid molecular species on mPTP opening. A, isolated mitochondria from failing hearts (n = 6) were preincubated for 10 min with 10 μm baic, 20 μm Ibu, or 40 μm MSPPOH for selective inhibition of lipoxygenase, cyclooxygenase, or cytochrome P450 enzymes, respectively. After preincubation, mitochondrial swelling was initiated by addition of Ca²⁺. **, p < 10⁻⁵, and ¶, p < 10⁻⁶ when compared with Ca²⁺ alone (Ctl). B, intact mitochondria from failing hearts were preincubated with 1 μm cyclosporine A (CsA) with or without 40 μm MSPPOH for 10 min at 25 °C. Mitochondrial swelling was monitored by addition of Ca²⁺ (left panel). The final ΔA₅₄₀ end-point measurements at 30 min are presented (right panel, n = 4–8). C, isolated mitochondria from non-failing control (n = 5) and failing hearts (n = 7) were preincubated with or without 40 μm MSPPOH for 10 min at 25 °C for inhibition of cytochrome P450(s). Mitochondrial swelling was monitored after addition of Ca²⁺ (left panel). The final ΔA₅₄₀ end point measurements at 20 and 30 min are presented in the middle and right panels, respectively (n = 4–8). §, p < 0.005. N.S., not significant. D, isolated mitochondria from failing hearts (n = 4) were preincubated for 10 min with 10 μm baic in the absence or presence of either 5-, 12-, 15-, or 20-HETE (4 μm final concentrations). Mitochondrial swelling was initiated by addition of Ca²⁺. Representative tracings for mitochondrial swelling and the absorbance decreases at 540 nm after 30 min of incubation are presented. *, p < 0.05, and **, p < 0.0005.