Respiratory control depression by tetraalkylammonium bromides in rat liver mitochondria.
Six different lipophilic (hydrophobic) organic cations, tetraethyl-, tetrapropyl, tetrabutyl-, tetrapentyl-, tetrahexyl-, and tetraheptylammonium bromide, depressed respiratory control in rat liver mitochondria. Evaluation of mitochondrial responses in terms of a quadratic equation in log P (an index of lipophilicity) indicated that the NADH dehydrogenase receptor site for inhibitor (diminution of control of glutamate, alpha-ketoglutarate, and beta-hydroxybutyrate respiration) was more lipophilic than receptor sites for flavin-linked substrates (reduction of control of succinate, choline and alpha-glycerophosphate respiration). The succinate dehydrogenase receptor site for inhibition by the tetraalkylammonium bromides was more hydrophillic (less lipophilic) than the choline or alpha-glycerophosphate dehydrogenase receptor sites. Depression of respiratory control may be a function of charge density and of lipophilicity at specific inner membranal sites and the susceptible site may differ for different respiratory substrates.
D000818:Animals; D002794:Choline / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000378:metabolism; D050356:Lipid Metabolism; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship
D005994:Glycerophosphates; D006885:Hydroxybutyrates; D007656:Ketoglutaric Acids; D000644:Quaternary Ammonium Compounds; D002794:Choline