Figure 7. DHODH activity. (A–C) Histochemical detection of DHODH activity in adult mouse brain. (A) Negative control, no dihydroorotate (DHO) added. (B) DHODH activity, DHO added. (C) DHODH activity inhibition, DHO and its inhibitor Brequinar (20 μM) added. (D) Oxygen consumption increment in adult mouse brain after addition of DHO; horizontal black line indicates significant difference. (E) Inhibition of oxygen consumption by leflunomide in brain homogenate with (green) and without (blue) addition of DHO. Dashed line (100 %) indicates mean values of oxygen consumption in uninhibited cells. Bars indicate oxygen consumption in leflunomide inhibited cells N = 3. *: p < 0.05 (versus uninhibited cells).