In vitro effects of nicotine on mitochondrial respiration and superoxide anion generation.
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.
Cormier
A
A
Laboratoire de Pharmacologie, Faculté de Médecine de Paris XII, F94 010, Créteil, France. a.cormier@univ-paris12.fr
Morin
C
C
Zini
R
R
Tillement
J P
JP
Lagrue
G
G
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
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