Rationale: Current conceptualizations of drug reinforcement assume that drug-taking behavior is a consequence of the contingent, temporal relationship between the behavior and drug reward. However, stimulant drugs also potentiate the rewarding effects of other reinforcers when administered noncontingently.
Objectives: These studies were designed to determine whether noncontingent nicotine enhances the reinforcing properties of a nonpharmacological reinforcer and whether this direct effect facilitates operant behavior within the context of a nicotine self-administration procedure.
Methods: Rats self-administered nicotine or food, or received noncontingent nicotine, saline, or food either with or without a response-contingent, unconditioned reinforcing visual stimulus (VS).
Results: Noncontingent nicotine, whether delivered as discrete injections based on a pattern of self-administered nicotine or as a continuous infusion, increased response rates maintained by the VS. There were no significant differences in responding by animals that received contingent compared with noncontingent nicotine when a VS was available. This increase was not observed in the absence of the VS or as a consequence of noncontingent food delivery. Operant behavior was equally attenuated and reinstated by the removal and subsequent replacement of contingent and noncontingent nicotine. Nicotine supported self-administration in the absence of response-contingent, nicotine-paired stimuli; however, response rates were drastically reduced compared with nicotine self-administration with the VS.
Conclusions: Nicotine influences operant behavior in two ways: by acting as a primary reinforcer when it is contingent upon behavior, and by directly potentiating the reinforcing properties of other stimuli through a nonassociative mechanism. Nicotine self-administration and smoking may be largely dependent upon this later action.
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http://dx.doi.org/10.1007/s00213-003-1473-3 | DOI Listing |
Front Behav Neurosci
November 2023
Department of Psychology, University of New Hampshire, Durham, NH, United States.
Previous reports have indicated the reciprocal effects of nicotine and ethanol on their rewarding and reinforcing properties, but studies using methodological approaches resembling substance use in vulnerable populations are lacking. In our study, rats first self-administered ethanol, and their sensitivity to ethanol's reinforcing effects was assessed using a reinforcer demand modeling approach. Subsequently, rats were equipped with intravenous catheters to self-administer nicotine, and their sensitivity to nicotine's reinforcing effects was evaluated using the same approach.
View Article and Find Full Text PDFJ Neurosci Methods
February 2024
Department of Psychiatry, University of California, San Diego, CA, USA. Electronic address:
Background: Despite extensive human use of inhalation for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization.
New Method: Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer.
Nicotine Tob Res
June 2023
Department of Psychiatry, University of Florida, Gainesville, FL, USA.
Introduction: Smoking and vaping throughout adolescence and early adulthood lead to nicotine dependence. Nicotine withdrawal is associated with somatic and affective withdrawal symptoms that contribute to smoking and relapse. Affective nicotine withdrawal symptoms in humans include craving for cigarettes, depression, anxiety, trouble sleeping, and cognitive deficits.
View Article and Find Full Text PDFNicotine Tob Res
April 2023
Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA.
Introduction: Nicotine and cannabis are commonly used together, yet few studies have investigated the effects of concurrent administration. Nicotine exhibits reinforcement enhancing effects by promoting the reinforcing properties of stimuli including other drugs. As many studies of this effect used non-contingent nicotine, we implemented a dual-self-administration model where rats have simultaneous access to two drugs and choose which to self-administer throughout a session.
View Article and Find Full Text PDFJ Pharmacol Exp Ther
November 2021
Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas (M.R.D., G.T.C.); South Texas Veterans Health Care System, San Antonio, Texas (M.R.D., G.T.C.); and Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, NIDA and NIAAA, Bethesda, Maryland (A.S., K.C.R.)
A subset of rats that self-administer 3,4-methylenedioxypyrovalerone (MDPV) develop unusually high levels of drug taking. A history of responding maintained by cocaine, but not food, prevents the development of this high-responder phenotype; however, it is unclear how histories of noncontingent cocaine exposure or self-administering drugs from other pharmacological classes would affect its development. In the current studies, 5 groups of male Sprague-Dawley rats were used to determine whether histories of responding maintained by drugs from different pharmacological classes (e.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!