Isolated cardiac complex I (A), complex II-III (B), complex V (C), citrate synthase (D), and aconitase activities (E) at 7 and 14 days after intrahippocampal DOM administration (gray bars) in rats, compared with 14 days after saline administration in controls (black bars). Data are expressed as means ± SEM of 8 separate experiments. ‡P < 0.05, ‡‡P < 0.01, and ‡‡‡P < 0.001 versus 14-day saline.