Human monoamine oxidase is inhibited by tobacco smoke: β-carboline alkaloids act as potent and reversible inhibitors - S… this explains why some people get depressed when they quit smoking cigarettes.... or at least correlates with very heavy smokers > 25 cigs a day. Which was me. MAO Key Reason for Depression When Smokers Quit | Medpage Today
That cigarette smoke effects every part of our bodies. Every part.