Related Experiment Video

Updated: Aug 18, 2026

Spectral Confocal Imaging of Fluorescently tagged Nicotinic Receptors in Knock-in Mice with Chronic Nicotine Administration
08:47

Spectral Confocal Imaging of Fluorescently tagged Nicotinic Receptors in Knock-in Mice with Chronic Nicotine Administration

Published on: February 10, 2012

Inhibiting CYP2A5 enzyme in mice decreases circulating cotinine after nicotine administration and increases dopamine

Lefteris C Zacharia1,2, Sotiris Ioannou3

  • 1Department of Health Sciences, School of Life and Health Sciences, University of Nicosia, Nicosia, Cyprus.

Xenobiotica; the Fate of Foreign Compounds in Biological Systems
|August 17, 2026
PubMed

Insights

8-methoxypsoralen (8-MOP) inhibits nicotine metabolism in mice, increasing dopamine levels. This suggests that inhibiting nicotine metabolism could aid smoking cessation by prolonging nicotine

Area of Science:

  • Pharmacology and Toxicology
  • Nicotine Metabolism and Smoking Cessation

Background:

  • Smoking cessation remains a significant public health challenge, with current methods like nicotine replacement therapy (NRT) often lacking personalization.
  • Individual differences in nicotine metabolism, particularly via the enzyme P450 2A6 (CYP2A6), influence smoking behavior and cessation success.
  • Fast nicotine metabolizers exhibit higher dependence and lower quit rates, highlighting the potential of modulating nicotine metabolism for smoking cessation.

Purpose of the Study:

  • To investigate the potential of Ginkgo biloba (GB), quercetin, and 8-methoxypsoralen (8-MOP) to inhibit nicotine metabolism *in vivo*.
  • To assess the impact of these compounds on serum cotinine levels, brain dopamine, and liver CYP2A5 activity in a mouse model.

Main Methods:

  • Mice were administered nicotine with or without GB, quercetin, or 8-MOP.
  • Serum cotinine levels, a marker of nicotine metabolism, were measured.
  • Brain dopamine levels and hepatic CYP2A5 activity were assessed.

Main Results:

  • 8-methoxypsoralen (8-MOP) significantly inhibited nicotine metabolism *in vivo* by 55% and increased brain dopamine levels.
  • Chronic administration of Ginkgo biloba (GB) and quercetin did not show detectable inhibition of nicotine metabolism.
  • Ginkgo biloba (GB) administration alone resulted in increased brain dopamine levels.

Conclusions:

  • 8-MOP demonstrates potential as an agent to inhibit nicotine metabolism, which may aid in reducing cigarette consumption.
  • Compounds that inhibit nicotine metabolism could enhance smoking cessation strategies by prolonging nicotine's presence and dopamine's effects.
  • Further research into nicotine metabolism inhibitors may lead to more personalized and effective smoking cessation therapies.
Keywords:
CYP2A5/2A6 activityGinkgo bilobaNicotine metabolismmethoxypsoralensmoking reduction

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