Impulsivity, sex, gonadal hormones, and dietary excesses have been shown to influence drug abuse. The purpose of the proposed experiments is to determine whether sex, gonadal hormones and excessive sweet intake influence impulsive choices for food and cocaine rewards in rats. A delay discounting procedure will be used in which responding on one lever will result in a small, immediate reward, while responses on the other lever will result in a larger reward after a response-dependent delay. The adjusting delay will be used as a quantitative measure of impulsivity. Experiment 1 will examine sex differences in performance of this task, and Experiment 2 will examine gonadal hormone effects. In Experiment 3, male and female rats bred for high and low saccharin consumption will be compared to study the relationship between sweet preference and impulsivity. It is hypothesized that female rats will be more impulsive than males, estrogen in female rats will correspond with higher levels of impulsivity, and rats with high saccharin intake will be more impulsive than low saccharin rats. Clarifying the relationship between impulsivity and other factors that influence drug abuse will aid in developing prevention and treatment strategies. ? ? ?
