Gietzen Dorothy W, Hao Shuzhen, Anthony Tracy G
Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Annu Rev Nutr. 2007;27:63-78. doi: 10.1146/annurev.nutr.27.061406.093726.
Animals reject diets that lead to indispensable amino acid (IAA) depletion or deficiency. This behavior is adaptive, as continued IAA depletion is incompatible with maintenance of protein synthesis and survival. Following rejection of the diet, animals begin foraging for a better IAA source and develop conditioned aversions to cues associated with the deficient diet. These responses require a sensory system to detect the IAA depletion and alert the appropriate neural circuitry for the behavior. The chemosensor for IAA deprivation is in the highly excitable anterior piriform cortex (APC) of the brain. Recently, the well-conserved general AA control non-derepressing system of yeast was discovered to be activated by IAA deprivation via uncharged tRNA in mammalian APC. This system provides the sensory limb of the mechanism for recognition of IAA depletion that leads to activation of the APC, diet rejection, and subsequent adaptive strategies.
动物会拒绝导致必需氨基酸（IAA）耗竭或缺乏的饮食。这种行为具有适应性，因为持续的IAA耗竭与维持蛋白质合成和生存不相容。在拒绝该饮食后，动物开始寻找更好的IAA来源，并对与缺乏饮食相关的线索产生条件性厌恶。这些反应需要一个感觉系统来检测IAA耗竭，并提醒适当的神经回路做出相应行为。IAA缺乏的化学传感器位于大脑高度兴奋的前梨状皮质（APC）中。最近发现，酵母中保守的一般氨基酸控制非抑制系统在哺乳动物APC中通过无电荷tRNA被IAA缺乏激活。该系统为识别IAA耗竭的机制提供了感觉环节，从而导致APC激活、饮食拒绝和随后的适应性策略。
