Understanding the stimulus effects of nicotine and bupropion in a drug-drug discriminated goal-tracking task.

Rationale: Bupropion is a non-nicotine medication for smoking cessation that has overlapping stimulus effects with nicotine as demonstrated in drug discrimination studies. Whether these shared stimulus effects will alter acquisition or maintenance of a discrimination between nicotine and bupropion is unknown.

Objective: We sought to test this possibility using the drug discriminated goal-tracking (DGT) task and whether discrimination training history affected generalization and substitution tests.

Effects of dopamine and serotonin synthesis inhibitors on the ketamine-, d-amphetamine-, and cocaine-induced locomotor activity of preweanling and adolescent rats: sex differences.

The pattern of ketamine-induced locomotor activity varies substantially across ontogeny and according to sex. Although ketamine is classified as an NMDA channel blocker, it appears to stimulate the locomotor activity of both male and female rats via a monoaminergic mechanism. To more precisely determine the neural mechanisms underlying ketamine's actions, male and female preweanling and adolescent rats were pretreated with vehicle, the dopamine (DA) synthesis inhibitor ∝-methyl--p-tyrosine (AMPT), or the serotonin (5-HT) synthesis inhibitor 4-chloro--phenylalanine methyl ester hydrochloride (PCPA).

Effects of monoamine depletion on the ketamine-induced locomotor activity of preweanling, adolescent, and adult rats: Sex and age differences.

Ketamine significantly increases the locomotor activity of rodents, however this effect varies according to the sex and age of the animal being tested. To determine the role monoamine systems play in ketamine's locomotor activating effects: (a) male and female preweanling, adolescent, and adult rats were pretreated with vehicle or the monoamine depleting agent reserpine (1 or 5 mg/kg), and (b) the behavioral actions of ketamine (20 or 40 mg/kg) were then compared to d-amphetamine (2 mg/kg) and cocaine (10 or 15 mg/kg). The ability of reserpine to deplete dorsal striatal dopamine (DA) and serotonin (5-HT) in male and female rats was determined using HPLC.

Effects of ketamine on the unconditioned and conditioned locomotor activity of preadolescent and adolescent rats: impact of age, sex, and drug dose.

Rationale: Ketamine is used by preadolescent and adolescent humans for licit and illicit purposes.

Objective: The goal of the present study was to determine the effects of acute and repeated ketamine treatment on the unconditioned behaviors and conditioned locomotor activity of preadolescent and adolescent rats.

Methods: To assess unconditioned behaviors, female and male rats were injected with ketamine (5-40 mg/kg), and distance traveled was measured on postnatal day (PD) 21-25 or PD 41-45.