Nornicotine is self-administered intravenously by rats

M. T. Bardo, T. A. Green, P. A. Crooks, L. P. Dwoskin

Research output: Contribution to journalArticlepeer-review

106 Scopus citations


Rationale: Nicotine is a tobacco alkaloid known to be important in the acquisition and maintenance of tobacco smoking. However, other constituents in tobacco may contribute to the dependence liability. Objective: The present report sought to determine whether nornicotine, a tobacco alkaloid and metabolite of nicotine, has a reinforcing effect. Methods: Rats were prepared with a jugular catheter, then were allowed to self- administer intravenously either S(-)-nicotine (0.03 mg/kg/infusion), RS(±)-nornicotine (0.3 mg/kg/infusion) or saline using a two-lever operant procedure. The response requirement for each infusion was incremented gradually from a fixed ratio 1 (FR1) to FR5. When responding stabilized on the FR5, other doses of nicotine (0.01 mg/kg/infusion and 0.06 mg/kg/infusion) and nornicotine (0.075, 0.15, and 0.6 mg/kg/infusion) were tested for their ability to control responding. Results: Similar to nicotine, rats self-administered nornicotine significantly above saline control levels. Within the dose ranges tested, both nicotine and nornicotine yielded relatively flat dose-response functions. Extinction of responding was evident when saline was substituted for nornicotine, and responding was reinstated when nornicotine again was available. The rate of nornicotine self-administration was similar between rats tested with either 24-h or 48-h inter-session intervals. Conclusion: These results indicate that nornicotine contributes to the dependence liability associated with tobacco use.

Original languageEnglish (US)
Pages (from-to)290-296
Number of pages7
Issue number3
StatePublished - 1999
Externally publishedYes


  • Drug reward
  • Nicotine
  • Nicotine metabolites
  • Nornicotine
  • Self-administration
  • Tobacco use

ASJC Scopus subject areas

  • Pharmacology


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