The effect of 1-(5'-oxohexyl)-3-methyl-7-propyl-xanthine on the respiratory activity of the rat brain mitochondria.

The effect of 1-(5'-oxohexyl)-3-methyl-7-propyl-xanthine (HWA 285) on the respiration and oxidative phosphorylation in mitochondria isolated from normal (CM), ischemic (IsM) and postischemic (PIsM) rat brain was investigated. After the administration of 10 mg/kg HWA 285 p.o. daily for 14 days the mitochondrial ATPase activity was significantly increased, whereas O2-consumption and the respiratory control rate (RCR) were decreased. In IsM the RCR was increased, if they consumed glutamate and malate as substrates (from 3.7 +/- 0.8 to 5.0 +/- 0.75) as consequence of increased oxygen consumption in status 3. The pretreatment of the rats with 10 mg/kg HWA 285 p.o. induced a normalization of RCR in mitochondria from ischemic brains. The RCR in PIsM was apparently not influenced by HWA 285 but the oxidative phosphorylation was slightly increased. These results are consistent with the assumption that HWA 285 exerts a modulative effect on the rat brain mitochondria dependent on their functional status.