Pharmacokinetic and pharmacodynamic analysis of d-amphetamine in an attention task in rodents.

Amphetamine is a common therapeutic agent for alleviating the core symptoms associated with attention-deficit hyperactivity disorder (ADHD) in children and adults. The current study used a translational model of attention, the five-choice serial reaction time (5-CSRT) procedure with rats, to examine the time-course effects of d-amphetamine. Effects of different dosages of d-amphetamine were related to drug-plasma concentrations, fashioned after comprehensive pharmacokinetic/pharmacodynamic assessments that have been employed in clinical investigations.

Further delineation between typical and atypical dopamine uptake inhibitors: effects on food-maintained behavior and food consumption.

The present studies compared the acute effects of benztropine analogs (4-Cl-BZT, JHW 007, AHN 1-055), which are atypical dopamine uptake inhibitors, with those of the standard dopamine uptake inhibitors GBR 12909 and cocaine, on the reinforcing efficacy of food and food intake in male Sprague-Dawley rats. Repeated drug effects of JHW 007 on food intake were also determined. The number of ratios completed under a progressive-ratio schedule of food delivery was used as an index of reinforcing efficacy.

Observing of chain-schedule stimuli.

A classical-conditioning account of the processes maintaining behavior under chained schedules entails a backward transmission of conditioned-reinforcement effects. Assessing this process in traditional chain schedules is limited because the response maintained by stimulus onset accompanied by each link in a chain schedule may also be maintained by the primary reinforcer. In the present experiment, an observing response was used to measure the conditioned-reinforcing effects of stimuli associated with a three-link chain variable-time (VT) food schedule, and resistance-to-change tests (extinction and prefeeding) were implemented to examine if a backward transmission of reinforcement effects occur.

An influence of delayed reinforcement on the effectiveness of psychostimulants to enhance indices of attention under a five-choice serial reaction time procedure in male rats.

The five-choice serial reaction time (5-CSRT) procedure has been considered a translational tool for assessments of the psychopharmacology of attention in preclinical research. Because greater sensitivity to delayed reinforcement may promote the development of attention-deficit/hyperactivity disorder (ADHD) symptoms, effects of reinforcer delay and psychostimulants on performances under a 5-CSRT procedure were determined. Male rats were trained to respond under a 5-CSRT procedure with different delay-of-reinforcement conditions (0, 2, 4, 8, 16 s), and effects of d-amphetamine, methylphenidate, and morphine (as a negative control) were assessed at 0- and 16-s delays.

Methylphenidate and impulsivity: a comparison of effects of methylphenidate enantiomers on delay discounting in rats.

Rationale: Current formulations of methylphenidate (MPH) used in treatment of attention-deficit/hyperactivity disorder (ADHD) result in significantly different bioavailability of MPH enantiomers. Daytrana®, a dl-MPH transdermal patch system, produces higher levels of l-MPH than when dl-MPH is administered orally (e.g.

A within-subject analysis of d-amphetamine exposure on delay discounting in rats.

Studies concerning the relation between stimulant drug exposure and subsequent delay discounting (impulsive choice) have resulted in mixed findings that could be related to the type of stimulant drug exposure or the use of between-subject comparisons. The purpose of the present study was to examine effects of prior D-amphetamine exposure on subsequent delay discounting using a within-subject assessment. Two groups of rats were trained under a discrete-trials choice procedure until delay discounting was stable.

Effects of acute and chronic methylphenidate on delay discounting.

Methylphenidate (MPH) is one of the most common therapeutics used for the treatment of attention-deficit/hyperactivity disorder (ADHD), which consists of symptoms of inattention, and/or impulsivity and hyperactivity. Acute administration of MPH has been found to decrease impulsive choice in both humans and nonhuman animals, however, little is known about potential long-term changes in impulsive choice due to chronic administration of MPH. In the present experiment, effects of acute and chronic MPH (1.

Effects of variable training, signaled and unsignaled delays, and d-amphetamine on delay-discounting functions.

One common procedure for obtaining delay-discounting functions consists of a choice between a larger reinforcer that is presented after an increasing delay and a smaller reinforcer that is always presented immediately within session. Repeating the same context of delay presentation (e.g.