The effects of dopamine D1 and D2 antagonists on conditioned place preference (CPP) and locomotor activity were assessed. A total of three experiments were conducted. In each experiment there were two conditioning days followed by a test day. The results indicate that DA D1 and D2 receptors have distictly different roles in the mediation of behavior.

The attribution of incentive salience to cues that become associated with drugs of abuse is a critical characteristic of individuals who may be vulnerable to drug addiction. Rodents with the propensity to sign track are thought to be vulnerable to drug abuse. The goal of the current work was to investigate whether sign trackers (STs) would acquire cocaine conditioned place preference (CPP) to a discrete cue using an avian species. In Experiment 1, sign and goal trackers (GTs) were first identified using a one third rank order split. Following identification, cocaine-CPP was conducted with a discrete cue in each end chamber. Contrary to previous research, results showed that GTs showed a CPP to the discrete cue but STs did not. Experiment 2 was conducted to determine whether sign and GTs had been misclassified with the rank order split. Experiment 2 compared the rank order method with a t-test method (absolute criterion). Misclassification of both sign and GTs occurred using the rank order split. The findings indicated that use of a more accurate method to identify sign and GTs may have led to different results for Experiment 1. The t-test method may be useful for models that require identification of STs.

The effects of the kappa opioid agonist U-50,488 on morphine-induced condtioned place preference (CPP), locomotor activity and Fos immunoreactivity and assessed in 10-, 17- and 35-day old rats. It was predicted that kappa agonist treatment would block the unconditioned and conditioned behaviors produced by morhine (a mu opioid receptor agonist).

This study investigated nicotine conditioned place preference (CPP) in two different ages of adolescence using a rodent model of schizophrenia. Both 2- and 3-chambered CPP apparatuses were used to test whether the CPP was due to an aversion to the white chamber. Animals were neontally treated with the dopamine D2/D3 agonist, quinpirole, or saline and raised to either early postweanling age (P 22) or adolescence (P 29). Rats were conditioned to prefer the white chamber using nicotine. Results showed that nicotine induced CPP and appeared to alleviate an increased stress response in D2 primed animals, which appeared to diminish over time. Additionally, adult D2 and non-D2 primed rats were tested on the elevated T-maze. Results revealed that D2 primed rats demonstrated a significant increase in unconditioned fear. This study showed that nicotine induced CPP in D2 and non-D2 primed rats regardless of age, and D2 primed rats appear to demonstrate an increase in stress levels that was alleviated by nicotine.