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* M DEPARTMENT OF HEALTH A HUMAN SERVICE Exhibit 7 



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National Inatitule on Drug Abuie 

 MOO Flahen Lane 

 4PR13 8M RockvHIa, Maryland 20SS7 



The Honorable Henry A. Waxman 

 Chairman, Subcommittee on 



Health and the Environment 

 Committee on Energy and Commerce 

 House of Representatives 

 Washington, D.C. 20515-6118 



Dear Mr. Waxman: 



I am writing in response to your request of April 11 for the evaluation by the National 

 Institute on Drug Abuse (NIDA) of the significance of the findings presented in 

 Dr. Victor DeNoble's 1983 research paper, "Nicotine as a Positive Reinforcer in Rats: 

 Effects of Infusion Dose and Fixed Ratio Sire.* The findings from Dr. DeNoble's study 

 demonstrate that nicotine does act in a reinforcing manner when tested in an animal model. 



It is also important to note that the rate of nicotine self-administration varied with the dose of 

 the drug. Furthermore, when the subject's baseline nicotine level was increased by the 

 researcher, the rate of self-administration of nicotine by the subject in the study was 

 decreased. These two findings support the contention that nicotine reinforcement was due to 

 the pharmacologic effects of this substance. These findings from the DeNoble study indicate 

 that nicotine has reinforcing properties, one of the hallmarlc characteristics of an addictive 

 drug, and are consistent with those of NIDA-supported researchers who have studied the 

 reinforcing effects of nicotine. 



You also requested my comments on the statement by the Phillip Morris Company that the 

 DeNoble study shows that "nicotine is a reinforcer in the class of nonaddictivc chemical 

 compounds such as saccharin or water.' It is tiue that saccharin and water can also serve as 

 reinforcers; however, the reinforcing properties of water depend upon the animals being 

 deprived of water and the reinforcing properties of saccharin are due to its ta.^te. In the 

 DeNoble study, the animals were neither food nor water deprived, and nicotine was 

 administered intravenously, which avoids taste effects. Therefore, nicotine docs not have the 

 same characteristics a^ water and saccharin. 



I hope you will find this information helpful. 



Sincerely, 



Alan I. Leshner, Ph.D. 

 Director 



