Comparison of three measurement models of discounting among individuals with methamphetamine use disorder.

Background And Objectives: Delay discounting is associated with numerous clinically significant aspects of substance use disorders (SUDs). Recent studies have demonstrated that different models for assessing discounting may result in disparate conclusions. The current study compared two discounting tasks: money now versus money later (M-M) and methamphetamine now versus money later (MA-M) among non-treatment seeking individuals (N = 59) with methamphetamine use disorder (MAUD).

A COMPARISON OF MAZUR'S AND AREA UNDER THE CURVE FOR DESCRIBING STEEP DISCOUNTERS.

Delay discounting describes how a reward loses value as a function of increasing delay to its receipt and has been reliably associated with a variety of vulnerable populations including those with substance use disorders (SUDs). Two commonly used models to assess delay discounting in the field of SUDs include log derived from Mazur's hyperbolic equation and area under the curve (AUC). In the current study, we compared log with AUC on delay discounting data obtained from non-treatment seeking, cocaine- and methamphetamine-dependent volunteers.

Differentiating the primary reinforcing and reinforcement-enhancing effects of varenicline.

Rationale: Varenicline (VAR), a smoking cessation aid that is a partial agonist at nicotinic receptors, mimics the reinforcement-enhancing effects of nicotine. Varenicline, when accompanied by non-drug cues, is self-administered by rats, though it is unclear whether this results from varenicline acting as a primary reinforcer or a reinforcement enhancer of the cues.

Objectives: This study sought to disentangle these two potential actions.

Nicotine enhances the expression of a sucrose or cocaine conditioned place preference in adult male rats.

Nicotine has been shown to enhance the motivational properties of non-nicotine stimuli. This reinforcement-enhancing property of nicotine has the potential to promote the use of other illicit substances as well as maladaptive patterns of food intake. Therefore, the current study aimed to examine whether nicotine enhances preference for contexts paired with cocaine or sucrose utilizing a place conditioning procedure.

Adolescent exposure to nicotine results in reinforcement enhancement but does not affect adult responding in rats.

Background: Adolescence is a period of development associated with a peak in an organism's responsiveness to reward. Epidemiological data indicate that the initiation of smoking is high during adolescence and that earlier age of onset is associated with increased incidence of dependence as adults. In rats, nicotine is known to have primary reinforcing and reinforcement enhancing effects.

Precipitated withdrawal from nicotine reduces reinforcing effects of a visual stimulus for rats.

Introduction: Research has identified at least two positive reinforcement-related effects of nicotine: (a) primary reinforcement and (b) enhancement of reinforcement from concurrently available stimuli. Prior examples of the reinforcement-enhancing effects with rats showed that repeated, intermittent nicotine exposure increased responding for non-nicotine reinforcers, and this effect remained robust over several weeks. However, the effects of continuous nicotine exposure on responding for a non-nicotine reinforcer are unknown, as are the effects of abruptly withdrawing continuous nicotine on behavior maintained by the same reinforcer.

Varenicline dose dependently enhances responding for nonpharmacological reinforcers and attenuates the reinforcement-enhancing effects of nicotine.

Introduction: Varenicline (VAR), a partial nicotinic agonist, is one of the most effective smoking cessation pharmacotherapies. The therapeutic efficacy of VAR could be partly the result of substituting for and/or blocking the reinforcement-enhancing effects of nicotine (NIC). We assessed the effects of VAR alone and in combination with NIC (0.

The reinforcement-enhancing effects of nicotine: implications for the relationship between smoking, eating and weight.

Concerns about body weight represent an important barrier to public health efforts aimed at reducing smoking. Epidemiological studies have found that current smokers weigh less than non-smokers, smoking cessation results in weight gain, and weight restriction is commonly cited as a reason for smoking. The mechanisms underlying the relationship between smoking and weight are complex and may involve a number of factors including changes in caloric intake, physical activity, metabolic rate, and lipogenesis.

Response topography in behavioral tolerance to cocaine with rats.

Research conducted with rats has shown tolerance to the behavioral effects of psychomotor stimulants to be contingent on chronic drug administration occurring before the experimental session. Recent experiments with pigeons, however, resulted in tolerance when drug administration followed the experimental session. We hypothesized that the apparent species differences in tolerance may be a function of different operantly conditioned response topographies used in these experiments.

Tolerance to effects of cocaine on behavior under a response-initiated fixed-interval schedule.

Tolerance to effects of cocaine can be modulated by schedules of reinforcement. With multiple ratio schedules, research has shown an inverse relationship between ratio requirement and amount of tolerance that resulted from daily administration of the drug. In contrast, tolerance to the effects of cocaine on behavior under multiple interval schedules generally has developed regardless of interval value.