Treatment (during daily place-conditioning sessions, alternating every other day with no food) | Treatment on test day (30 min before place preference expression testing) | Time spent in chambers on test day4-a | |
---|---|---|---|
Food-paired4-b | No-food-paired | ||
No food | Vehicle4-c | 7.9 ± 0.9 | 7.1 ± 0.9 |
Food4-b | Vehicle4-c | 9.6 ± 0.54-150 | 5.4 ± 0.5 |
Food4-b | SB-277011-A (10 mg/kg) | 9.6 ± 0.44-150 | 5.4 ± 0.4 |
↵F4-a Each value represents mean time (minutes) spent in each chamber ± SEM on the test day. Total possible combined time in both chambers was 15 min. Ten rats were examined for each treatment pairing. Froot Loops, a sweetened fruit-flavored breakfast cereal that is highly appetitive to laboratory rats, was used as the food. During conditioning, animals were exposed to the food-paired (5 daily 30 min sessions) and no-food-paired (5 daily 30 min sessions) chambers on alternating days. Half of the food-exposed animals received food in one cue-distinctive environmental chamber; the other half received it in the other chamber. The no food/no food animals received no food in each cue-distinctive chamber on alternating days. On the test day, animals received either vehicle or SB-277011-A 30 min before being placed in the CPP apparatus and tested for expression of place conditioning.
↵F4-b Froot Loops.
↵F4-c Methylcellulose solution (2% w/v; 1 ml/kg, i.p.).
↵F4-150 Significantly different from time spent in the food-paired chamber on the test day by animals given no food/no food alternating place-conditioning sessions plus vehicle before place preference expression testing, p < 0.05, ANOVA and Student–Newman–Keuls test.