Department of Psychology, Boston College, Chestnut Hill, MA 02467-3807, United States.
Physiol Behav. 2011 Oct 24;104(5):996-1001. doi: 10.1016/j.physbeh.2011.06.020. Epub 2011 Jul 1.
Fear inhibits food intake. Cessation of eating in anticipation of danger is an adaptive response that prepares an organism for an imminent threat, but it could become maladaptive when persistent. To begin to examine the underlying mechanisms, we developed an animal model for fear-cue induced inhibition of feeding. In that preparation, food-deprived rats stop eating when presented with a tone that signals a foot-shock based on prior associations. Here, we examined whether there are sex differences in adult male and female rats. We found that female rats showed sustained fear-cue induced feeding inhibition compared to males during the extinction. During the first of four extinction tests with tone presentations, both male and female rats showed similar, robust cessation of eating. Rats of both sexes that previously received tone-shock pairings ate significantly less than the control rats that received tones without shocks during training. Male rats extinguished this behavior during the second test, while females continued to show the effect during the second and third tests, and extinguished during the fourth test. The findings provide a novel framework for investigation of sex differences in the control of feeding and the underlying brain substrates. The animal model may also be informative for understanding human eating and associated disorders. In particular, the potential contribution of fear in the maintenance of low food intake in anorexia nervosa is hypothesized.
恐惧抑制进食。预期危险时停止进食是一种适应性反应，可使机体为即将到来的威胁做好准备，但当持续存在时，这种反应可能会变得适应不良。为了开始研究潜在的机制，我们开发了一种用于恐惧线索诱导进食抑制的动物模型。在该准备中，当食物剥夺的大鼠听到与之前的关联有关的预示着足底电击的声音时，就会停止进食。在这里，我们检查了成年雄性和雌性大鼠是否存在性别差异。我们发现，与雄性大鼠相比，雌性大鼠在消退期间表现出持续的恐惧线索诱导的进食抑制。在四次带有声音呈现的消退测试中的第一次中，雄性和雌性大鼠都表现出类似的、强烈的进食停止。与在训练中接受无电击的声音的对照组大鼠相比，之前接受过声音-电击配对的大鼠吃得明显少。雄性大鼠在第二次测试中消除了这种行为，而雌性大鼠在第二次和第三次测试中仍继续表现出这种效果，并在第四次测试中消除了这种效果。这些发现为研究进食控制和潜在的大脑基础中的性别差异提供了一个新的框架。该动物模型也可能有助于理解人类的进食和相关障碍。特别是，有人假设恐惧在神经性厌食症中维持低食物摄入方面的潜在作用。
