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According to one study, the nicotine present in a single cigarette is enough to block the production of estrogen in women. This action of nicotine on the brain could partly explain women’s greater difficulty in quitting smoking.
This finding was presented by the study’s lead author, Professor Erika Comasco of Uppsala University, Sweden, at the 35e edition of the congress of the European College of Neuropsychopharmacology (ECNP).
Small cohort of women
To reach this conclusion, the researchers worked on a group of ten women, volunteers and in good health. They received a dose of nicotine through the nose, and at the same time an injection of a radioactive tracer attached to a molecule that binds to the aromatase enzyme: aromatase, also called “estrogen synthase”, is the enzyme responsible for estrogen production.
Then these women were subjected to two medical imaging examinations: an MRI and a PET scan, in order to visualize the amount of aromatase and its location in the brain, thanks to the radioactivity emitted by the tracer.
This is how the effect on the thalamus, which is part of the limbic system of the brain, was demonstrated. This system is involved in behavioral and emotional responses.
Preliminary results
The researchers found that a single dose of nicotine moderately reduced the amount of aromatase in the brain.
“For the first time, we can see that nicotine acts to shut down the mechanism of estrogen production in the brains of women. We were surprised to see that this effect could be observed even with a single dose of nicotine, equivalent to a single cigarette, showing how powerful the effects of smoking are on a woman’s brain. This is a newly discovered effect, and it’s still preliminary work. We still don’t know what the behavioral or cognitive; only that nicotine acts on this area of the brain, but we note that the affected brain system is a target for addictive drugs, such as nicotine” details Erika Comasco, who adds that no man was included in this work.
Women more prone to relapse
Scientists already know that women and men are different when it comes to quitting smoking. Women are more resistant to nicotine replacement therapy and show a greater tendency than men to relapse when trying to quit smoking.
For Professor Comasco, “this discovery leads us to believe that the effect of nicotine on estrogen production has a significant impact on the brain, but perhaps also on other functions, such as the reproductive system – we don’t know yet […]. We now need to understand if this action of nicotine on the hormonal system is involved in any of these reactions.” she concludes.