title: In vitro effects of nicotine on mitochondrial respiration and superoxide anion generation.
abstract: In this study, we investigated the effects of nicotine on rat brain mitochondria. The polarographic studies determined the effects on the respiratory chain, whereas enzymatic assays and [3H]-nicotine binding allowed us to precisely identify its target and site of action. The measurements of oxygen consumption showed a significantly concentration-dependent inhibition by nicotine (EC50 was 4.95x10(-11) M), and a maximal decrease of 23.90% at 10(-7) M. Nicotine bound to complex I of the respiratory chain and inhibited the NADH-Ubiquinone reductase activity. We also showed that nicotine and NADH were competitive on complex I. Effects of cotinine, the main nicotine metabolite, and nornicotine, were also investigated: nornicotine inhibited the mitochondrial respiration whereas cotinine did not. Because the complex I generates superoxide anion, we investigated the effects of nicotine, following NBT oxidation, and showed that nicotine was able to inhibit this reactive oxygen species (ROS) generation by 15.74% with an EC50 of 2.02x10(-11) M. In conclusion, the present study shows that nicotine interacts with the complex I of brain mitochondrial respiratory chain and decreases ROS generation. This may explain a part of the beneficial and protective effects of nicotine in few neurodegenerative diseases, as suggested by many epidemiological studies.
authors.affiliation: Laboratoire de Pharmacologie, Faculté de Médecine de Paris XII, F94 010, Créteil, France. a.cormier@univ-paris12.fr
authors.forename: A
authors.initials: A
authors.lastname: Cormier
authors.forename: C
authors.initials: C
authors.lastname: Morin
authors.forename: R
authors.initials: R
authors.lastname: Zini
authors.forename: J P
authors.initials: JP
authors.lastname: Tillement
authors.forename: G
authors.initials: G
authors.lastname: Lagrue
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D000880:Anthraquinones / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D001392:Azocines; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002352:Carrier Proteins; D003367:Cotinine / Q000494:pharmacology; D042967:Electron Transport Complex I; D042963:Electron Transport Complex II; D018738:Hexamethonium / Q000494:pharmacology; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases; D009097:Multienzyme Complexes / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology; D009538:Nicotine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D010088:Oxidoreductases / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D016548:Prosencephalon / Q000648:ultrastructure; D011725:Pyridines / Q000494:pharmacology; D011807:Quinolizines; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D000093843:Quinolizidine Alkaloids
chemical_list: D000251:Adenosine Triphosphatases; D000470:Alkaloids; D000880:Anthraquinones; D000968:Antimycin A; D001392:Azocines; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002352:Carrier Proteins; D003367:Cotinine; D042967:Electron Transport Complex I; D042963:Electron Transport Complex II; D018738:Hexamethonium; D008565:Membrane Proteins; D025261:Mitochondrial Proton-Translocating ATPases; D009097:Multienzyme Complexes; D009243:NAD; D009247:NADH, NADPH Oxidoreductases; D018696:Neuroprotective Agents; D009538:Nicotine; D010088:Oxidoreductases; D011725:Pyridines; D011807:Quinolizines; D017382:Reactive Oxygen Species; D011978:Receptors, Nicotinic; D012402:Rotenone; D013385:Succinate Dehydrogenase; D013481:Superoxides; C004712:cytisine; D000093843:Quinolizidine Alkaloids; C005311:nornicotine; C020439:oligomycin sensitivity-conferring protein; C082748:epibatidine; C020491:rhein