Boakes Robert A, Rehn Simone, Badolato Connie, Rooney Kieron B
School of Psychology, University of Sydney, Australia.
School of Psychology, University of Sydney, Australia.
Physiol Behav. 2020 May 1;218:112822. doi: 10.1016/j.physbeh.2020.112822. Epub 2020 Jan 28.
Rats first given 24-h access to 10% sucrose for 4 or 12 days (Stage 1) were then switched to a saccharin solution for a 12-day Stage 2. The initial result of this switch was that these Sucrose groups drank less saccharin than Water groups that had been given only water to drink in Stage 1. This difference was maintained throughout Stage 2 by the females that served in Experiments 1 and 4 and by the males that served in Experiment 3. Experiment 1 also found that access to 10% glucose in Stage 1 produced an essentially identical decrease in subsequent saccharin acceptance as that produced by giving 10% sucrose in Stage 1. The impact on subsequent acceptance of saccharin was also tested in rats given two types of maltodextrin solution. The first type of maltodextrin (Myopure brand) was used with the males in Experiment 2; this failed to find any difference between the Maltodextrin and the Water group. However, when a second type of maltodextrin (SolCarb brand) was given to males in Stage 1 of Experiment 3, the results for this group were similar to those from a group given sucrose in Stage 1. The final experiment confirmed that prior exposure to maltodextrin solutions can reduce saccharin acceptance by female rats. Overall, the results suggest that acceptance of saccharin is sensitive to a contrast effect, in that it is reduced by prior exposure to a solution that is more palatable but not necessarily sweet.
首先，让大鼠在4天或12天内（第1阶段）每天有24小时接触10%的蔗糖，然后在第2阶段的12天内换成糖精溶液。这种转换的初步结果是，这些蔗糖组饮用的糖精比在第1阶段只给饮水的水组少。在实验1和4中参与实验的雌性大鼠以及在实验3中参与实验的雄性大鼠在整个第2阶段都保持了这种差异。实验1还发现，在第1阶段接触10%的葡萄糖，在随后糖精接受度上产生的降低与在第1阶段给予10%蔗糖产生的降低基本相同。对糖精随后接受度的影响也在给予两种麦芽糊精溶液的大鼠中进行了测试。第一种麦芽糊精（Myopure品牌）用于实验2中的雄性大鼠；该实验未发现麦芽糊精组和水组之间有任何差异。然而，当在实验3的第1阶段给雄性大鼠使用第二种麦芽糊精（SolCarb品牌）时，该组的结果与在第1阶段给予蔗糖的组相似。最终实验证实，先前接触麦芽糊精溶液会降低雌性大鼠对糖精的接受度。总体而言，结果表明糖精的接受度对对比效应敏感，即先前接触更可口但不一定甜的溶液会降低其接受度。
