Effects of Chronic Stress and Time of Day on Preference for Sucrose

摘要

Stress is thought to affect the quantity and preference for food in humans. Inthis experiment, rats were allowed to leverpress for two types of food pellets of equivalent caloric value but different sucrose content during a 16 day baseline and then a 14 day period of stress. The chronic stressor was signalled around-the-clock intermittent footshock. One group of rats had control over stressor termination while a second group was yoked to the escape performance of the rats in the first group. We have previously reported that rats in this model of chronic stress tolerate the paradigm well, continuing to gain weight, eat, drink water, and groom and escape more than 99% of the trials presented. During the prestress baseline period, the sweeter pellet was preferred by most rats but differences in preference among rats and in preference at different times of day were observed. The preference for the high sucrose pellet was most marked in the hours preceding lights off. Overall, no changes in food preference were seen as a function of stress condition during the 14 day stress period, Stress, Sucrose, Food preference.