Rationale: Because of the adverse effects of smoking during pregnancy, understanding the factors that influence maternal smoking may help in developing better treatments to help women quit smoking during pregnancy. Animal models could be useful for this purpose. Objective: The purpose of the present study was to begin the development of an animal model of smoking during pregnancy by initially characterizing nicotine self-administration (NSA) in pregnant rats. Another purpose was to begin to explore the effects of pregnancy on nicotine pharmacokinetics in rats. Materials and methods: In experiment 1, female rats self-administering nicotine during 23-h sessions were examined throughout gestation and lactation. In experiment 2, locomotor activity was measured during pregnancy to assess further potential motor effects of pregnancy. Experiments 3 and 4 compared the single-dose pharmacokinetics of nicotine in male, nonpregnant female, and pregnant females in the first and third trimester of pregnancy and the first week of lactation. Results: NSA decreased over the course of pregnancy with NSA significantly lower in the third trimester compared to nonpregnant controls. NSA remained suppressed for up to 10 days into lactation. Locomotor behavior was also significantly suppressed during the second and third trimesters and throughout lactation. Nicotine elimination was slower in pregnant females compared to nonpregnant females only in the third trimester. Conclusions: NSA, locomotor behavior, and nicotine elimination in rats are decreased during late pregnancy. The present study is the first to characterize NSA during pregnancy in animals, providing a potential model of maternal smoking in humans.
Bibliographical noteFunding Information:
Minneapolis Medical Research Foundation, 914 South 8th Street, D3-860, Minneapolis, MN 55404, USA e-mail: email@example.com
Acknowledgements The authors thank Cormac Kehoe, Matthew Dufek, Thomas Bramwell, and Dr. Victoria Kane for their technical assistance during the course of these experiments. The authors also thank Dr. Sharon Murphy for the helpful comments on an earlier version of the manuscript. This study was supported by NIDA grants P50-DA013333 and DA15668.
- Locomotor activity
- Nicotine self-administration