Davidson T L, Flynn F W, Grill H J
Department of Psychology, University of Pennsylvania.
Behav Neurosci. 1988 Feb;102(1):134-40. doi: 10.1037//0735-7044.102.1.134.
In three experiments we assessed the degree to which ad lib feeding, injection of cholecystokinin (CCK), and injection of lithium chloride (LiCl) produce states with similar sensory consequences. In each experiment, two groups of rats were trained to use cues arising from food deprivation and satiation as discriminative signals for shock. One group was shocked when deprived but not when nondeprived. The other group received the reversed discrimination. Testing began when incidence of freezing was greater under the shocked deprivation than under the nonshocked deprivation condition. In Experiment 1, the rats were tested under 24-hr food deprivation after injections of CCK, LiCl, and saline (in counterbalanced order). We reasoned that if either CCK or LiCl induce satiety-like states, they should promote patterns of responding different from those produced by saline but similar to those produced by ad lib feeding. The effects of CCK on freezing did not differ from those of saline, whereas both CCK and LiCl had effects that were different from ad lib feeding. This pattern of results was also obtained when deprivation level during training and testing was reduced to 8 hr (Experiment 1A) and also when rats received small amounts of food in conjunction with CCK (Experiment 2). The intubation of a high-calorie stomach load (Experiment 1A) produced a response profile like that observed after free feeding. Freezing after LiCl treatment differed from that observed after free feeding and from that found after injection of CCK. The results indicate that rats can differentiate between the sensory consequences of the states produced by CCK, by LiCl, and by ad lib feeding.
在三项实验中，我们评估了随意进食、注射胆囊收缩素（CCK）和注射氯化锂（LiCl）所产生的状态在感觉后果方面的相似程度。在每项实验中，两组大鼠被训练利用由食物剥夺和饱腹感产生的线索作为电击的辨别信号。一组在被剥夺食物时受到电击，未被剥夺时则不电击。另一组接受相反的辨别训练。当在电击剥夺条件下的僵住发生率高于非电击剥夺条件时，测试开始。在实验1中，大鼠在注射CCK、LiCl和生理盐水（按平衡顺序）后，在24小时食物剥夺状态下接受测试。我们推断，如果CCK或LiCl诱导出类似饱腹感的状态，它们应该会促进与生理盐水产生的反应模式不同，但与随意进食产生的反应模式相似的反应模式。CCK对僵住的影响与生理盐水的影响没有差异，而CCK和LiCl的影响都与随意进食不同。当训练和测试期间的剥夺水平降至8小时（实验1A）以及大鼠在注射CCK时同时摄入少量食物（实验2）时，也得到了这种结果模式。插入高热量胃负荷（实验1A）产生的反应模式与随意进食后观察到的相似。LiCl处理后的僵住与随意进食后观察到的以及注射CCK后观察到的不同。结果表明，大鼠能够区分CCK、LiCl和随意进食所产生状态的感觉后果。
