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| The Regulation of Drug Taking by Humans and Other Animals |
| Tuesday, May 30, 2006 |
| 9:00 AM–10:20 AM |
| Piedmont |
| Area: BPH; Domain: Basic Research |
| Chair: Steven I. Dworkin (University of North Carolina, Wilmington) |
| Discussant: Steven I. Dworkin (University of North Carolina, Wilmington) |
| CE Instructor: Steven I. Dworkin, Ph.D. |
| Abstract: Several different mechanisms have been proposed to account for the different patterns of drug intake observed in humans and other animals. Recently it has been proposed that drug intake is the result of both sensitization and habituation to the drug during consumption. Factors controlling human cigarette smoking and nicotine consumption by rats will be presented and discussed in the context of specific notions related to the regulation of drug intake. |
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| Sex Differences in a Rat Model of Adolescent-Onset Nicotine Self-Administration. |
| AMIR REZVANI (Duke University Medical Center), Susan Lawrence (Duke University Medical Center), Ann Petro (Duke University Medical Center), Jed E. Rose (Duke University Medical Center), Edward Levin (Duke University Medical Center) |
| Abstract: The vast majority of tobacco addiction begins during adolescence, and 88% of current smokers smoke their first cigarette before age 18 and 60% before age 14 (CDCP, 1991, 1998a, 1998b). Effects of nicotine during adolescence can be critical in determining the tenacity of addiction through the rest of life. Important neurobehavioral development is still occurring during the adolescent period. Critical differences between adolescent and adult neural function may underlie adolescent vulnerability to nicotine addiction. Adolescent neurobehavioral function may predispose individuals to greater nicotine self-administration than adults. This project was aimed at developing a rat model in which the neurobehavioral basis of adolescent vulnerability to nicotine addiction can be studied. Previously, we found that beginning nicotine SA during adolescence vs. adulthood caused a significant increase in SA that persisted through the period when the female adolescent rats became adults (Levin et al. Psychopharmacology, 169:141-149, 2003). In the current study, we showed that adolescent male rats have an even higher rate of nicotine SA during adolescence vs. adulthood than females. In male rats, the adolescent-onset group had more than triple the rate of nicotine SA than the adult-onset group during the first two weeks of SA. Then, over the third and fourth weeks of the study, as the male adolescent rats aged into young adulthood, their nicotine SA reduced toward the levels seen in older male rats, which started nicotine SA in adulthood. Both male and female rats increased nicotine SA with adolescent-onset. But, there is a sex difference with higher nicotine SA during adolescence in males and greater persistence of high nicotine SA into adulthood in females. This rat model can be used as an arena to determine the critical neurobehavioral underpinnings for vulnerability of both adolescent males and females to nicotine addiction. |
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| Factors Involved In Regulating the Intake Of Drug And Non-Drug Reinforcers. |
| STEVEN I. DWORKIN (University of North Carolina, Wilmington) |
| Abstract: The suggestion of similarities in the reinforcing effects of drug and non-drug reinforcers was initially used to justify the extension of research findings from the experimental analysis of non-drug reinforcers to substance abuse research. Undeniably behavioral studies evaluating the reinforcing effects of psychoactive drugs demonstrated and extended the similarities between these two broad classes of maintaining events. Moreover, current neurobiological mechanisms suggested to be involved in drug abuse are similar to those suggested to be involved in the reinforcing effects of non-drug reinforcers. This presentation will review evolutionary, behavioral and neurochemical theories of reinforcement related to food regulation and drug intake and present some of the similarities and differences between different drug and non-drug reinforcers that are involved in the regulation of intake. |
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| The Role of Nicotine and Non-Nicotine Factors in the Regulation of Cigarette Smoking Behavior. |
| JED E. ROSE (Duke University Medical Center) |
| Abstract: Cigarette smokers exhibit a fairly consistent regulation of smoke intake, and this behavior has been widely thought to reflect self-regulation of nicotine levels. However, recent studies suggest that non-nicotine factors, including sensory cues accompanying smoke inhalation, play a large role in regulating smoking behavior. Studies will be described that dissociate nicotine and non-nicotine influences, using methods entailing intravenous nicotine administration and presentation of denicotinized cigarettes. In these studies, the effects of non-nicotine components in limiting smoke intake were found to be significantly greater than the direct effects of nicotine, suggesting that conditioned cues may play a prominent role in the regulation of smoking behavior as well as tobacco dependence. These results also suggest novel lines of therapeutic development for smoking cessation treatment. |
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