Effect of nicotine and cotinine on the production of oxygen free radicals by neutrophils in smokers and non-smokers

1 Neutrophils play a role in the pathogenesis of ulcerative colitis. Most of the patients with ulcerative colitis are non-smokers. 2 Neutrophil function was examined in healthy males, five smokers and five non-smokers, measuring production of oxygen free radicals by chemiluminescence. 3 The chemiluminescence was examined in the presence of nicotine and its main metabolite cotinine in various concentrations. 4 10 mM nicotine inhibited production of oxygen free radicals (90.2% ± 11.6) compared with controls (P < 0.001), as did the same concentration of cotinine (58.9% ± 34.2), (P < 0.05). 5 1 mM solutions had no effect and 3 mM nicotine was required to achieve 50% inhibition. 6 Smokers and non-smokers did not differ. 7 Since plasma concentrations of nicotine after a cigarette are only between 5 and 15 mM, the observed effects of nicotine and cotinine in much higher pharmacological concentrations in this system are unlikely to be of clinical relevance in ulcerative coliti