Expression data from the basolateral amygdala of Long-Evans rats with a history of limited intermittent sucrose snacks

To study the molecular mediators of naturally rewarding effects of palatable food we used a model of palatable snacking (Ulrich-Lai et al., 2007) in which rats are given chronic, brief access to a limited amount of sucrose solution (30%). Single housed, male Long-Evans rats (250g) (n=12 per group) from Harlan Labs (Indianapolis, IN) received normal rat chow (Harlan Teklad) and water ad libitum for the duration of the experiment. After a one-week period of acclimation, rats were randomly assigned to drink treatment groups of either 30% sucrose solution or water. Rats received a 14-day regimen of twice daily (9:30 and 15:30) brief (maximum of 30 minutes) limited (up to 4 mL) access of their assigned drink solution. Drink solutions were delivered via a graduated sipper placed onto the cage top in addition to the existing water bottle and sippers were immediately removed when the animal had consumed 4mL or after the 30-minute access period, whichever occurred first. Drink intake, food intake, and body weight were monitored throughout the experiment to verify that the rats learned to drink sucrose, that they adjusted chow intake for calories consumed from sucrose (~10%), and that there was no effect on body weight gain as is normally seen with this model (Ulrich-Lai et al., 2007). Drink treatment terminated on day 14 and at 8:00 on the morning of day 15, the rats were sacrificed by rapid decapitation. BLA tissue was dissected, RNA extracted, and gene expression changes between water and sucrose groups were accessed by microarray.

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Ulrich-Lai YM, Christiansen AM, Ostrander MM, Jones AA, Jones KR, Choi DC, Krause EG, Evanson NK, Furay AR, Davis JF, Solomon MB, de Kloet AD, Tamashiro KL, Sakai RR, Seeley RJ, Woods SC, Herman JP