Beverly J L, Gietzen D W, Rogers Q R
Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis 95616.
Am J Physiol. 1990 Oct;259(4 Pt 2):R709-15. doi: 10.1152/ajpregu.1990.259.4.R709.
The mechanisms underlying the reduced intake of an amino acid-imbalanced diet (imbalanced diet) appears to involve a decrease in the content of the dietary limiting amino acid (DLAA) in the prepyriform cortex (PPC). Intake of imbalanced diet was increased from 45-50 to 70-75% of baseline after bilateral injection of the DLAA directly into the PPC, following an inverted U-shaped dose-response curve. Injections had no effect on intake of basal diets. Injection of the DLAA into the PPC reversed the aversion to imbalanced diet in choice studies, as rats selected an imbalanced diet over protein-free diet after such injections. Intake of imbalanced diet did not increase after a nonlimiting amino acid was injected into the PPC or after injections of the DLAA into other brain areas. Results were similar when either threonine or isoleucine was the DLAA. These results confirm that the decrease in the concentration of the DLAA in the PPC is involved in the reduction in intake of imbalanced diets.
氨基酸不平衡饮食（不均衡饮食）摄入量减少的潜在机制似乎涉及梨状前皮质（PPC）中膳食限制氨基酸（DLAA）含量的降低。在将DLAA双侧直接注射到PPC后，不均衡饮食的摄入量从基线的45 - 50%增加到70 - 75%，呈现倒U形剂量反应曲线。注射对基础饮食的摄入量没有影响。在选择研究中，向PPC注射DLAA可逆转对不均衡饮食的厌恶，因为注射后大鼠会选择不均衡饮食而非无蛋白饮食。向PPC注射非限制氨基酸或向其他脑区注射DLAA后，不均衡饮食的摄入量并未增加。当苏氨酸或异亮氨酸为DLAA时，结果相似。这些结果证实，PPC中DLAA浓度的降低与不均衡饮食摄入量的减少有关。
