Mark G Lesage

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Animal models of tobacco dependence typically rely on parenteral administration of pure nicotine. Models using cigarette smoke inhalation might more accurately simulate nicotine exposure in smokers. The primary goal of this study was to validate methods for administering cigarette smoke to rats using exposure conditions that were clinically relevant and(More)
RATIONALE Compensatory smoking may represent an adverse consequence of smoking reduction or the use of reduced-nicotine tobacco products. Factors contributing to individual variability in compensation are poorly understood. OBJECTIVE The objective of this study was to examine whether severity of nicotine withdrawal as measured by elevated intracranial(More)
The effects of chlorpromazine (0, 2, 6, and 10 mg/kg) on the acquisition of lever-press responding by rats were examined under conditions where reinforcement (water delivery) was immediate or delayed. Under the immediate reinforcement condition, water-deprived rats were exposed during 8-h sessions to a fixed-ratio 1 (FR 1) schedule of water delivery without(More)
RATIONALE Animals trained to self-administer a variety of addictive drugs exhibit a temporary increase in response rate when saline is substituted for the drug (i.e., an "extinction burst"). However, the presence of an extinction burst in animal models of nicotine self-administration (NSA) has not been studied extensively. OBJECTIVE The objective of the(More)
Previous studies have shown that ratio size influenced the development of tolerance under simple and multiple schedules, but not under progressive-ratio (PR) schedules. PR schedules share certain features with mixed-ratio (MR) schedules, and pilot data suggested that ratio size fails to modulate tolerance to cocaine or morphine under MR schedules. The(More)
RATIONALE Reinforcing abstinence from drug use with alternative nondrug reinforcers (e.g., contingency management) is one of the most effective interventions for drug abuse. While nonhuman studies have also shown that access to alternative nondrug reinforcers reduces drug self-administration, this effect has not been examined in nicotine self-administration(More)
The present study examined the effects of morphine in pigeons responding under a progressive-ratio 25 schedule of food delivery. Morphine initially reduced response rates and breaking points. With chronic exposure, tolerance developed to these effects. The magnitude of the observed tolerance was not obviously different from that previously reported under a(More)
Although progressive-ratio schedules have often been used by behavioral pharmacologists to index the relative reinforcing effects of drugs of abuse, they have been ignored in the study of tolerance to opioids. The present study examined tolerance to morphine in pigeons responding under a progressive-ratio 5 schedule of food delivery. Acute administrations(More)
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(More)
Over 25 years ago, B. F. Skinner introduced the concept of rule-governed behavior, which is the topic of this commentary. To date, behavioral pharmacologists have given rule-governed behavior little consideration in their analyses of drug action. There are, however, published studies that demonstrate the importance of rule-governed behavior in modulating(More)
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