Figure 6.

The Complex I bypass activity of two naphthoquinones is absent in cortical neurons that lack NQO1. A–F, OCR measurements from neurons and astrocytes in response to the injection of vehicle (“0 μm”) or the indicated concentrations of alpha-tocopherolquinone (α-TPQ; A and B), 2-methoxy-1,4-naphthoquinone (MNQ; C and D), or 2-methoxy-3-methyl-1,4-naphthoquinone (Me-MNQ; E, F). Subsequent injections consisted of 2,4-dinitrophenol (DNP; 150 μm) + pyruvate (Pyr; 10 mm), piericidin A (Pier A; 500 nm), and antimycin A (AA; 1 μm). Data are the mean ± SE from three to eight independent experiments.