Blevins J E, Dixon K D, Hernandez E J, Barrett J A, Gietzen D W
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, and Food Intake Laboratory, University of California, Davis, CA 95616, USA.
Brain Res. 2000 Oct 6;879(1-2):65-72. doi: 10.1016/s0006-8993(00)02734-7.
Previous work from this laboratory suggests that animals decrease their intake of an amino acid imbalanced diet (IMB), due in part to a drop in the concentration of the dietary limiting amino (DLAA) in the anterior piriform cortex (APC). Administration of the DLAA, but not of a non-limiting amino acid into the APC, blocks the anorectic response to IMB. To our knowledge, the effects of DLAA injections on intake of a diet devoid of the DLAA (DEV), have not been examined in areas outside the APC. We hypothesized that the LH is a potential chemosensory area for DLAA. Our objectives were: (1) to determine whether injections of the DLAA threonine into the lateral hypothalamus (LH) alter intake of a threonine-devoid diet (DEV); and (2) to examine the dose-response effects of threonine injections into the LH on intake of threonine-corrected diet (COR). Administration of threonine into the LH stimulated DEV intake during the first 6 h at the 0.25 and 1-nmol doses by approximately 26 and 24%, respectively. Threonine (0.25, 2.5 nmol) did not alter COR intake at any time during the first 12 h. Our results suggest that: (1) the LH, along with the APC, likely acts as a chemosensory brain area for indispensable amino acids; and (2) both the APC and LH are part of a circuit that is involved in the short term anorectic response to amino acid imbalanced diets.
该实验室之前的研究表明，动物会减少对氨基酸失衡饮食（IMB）的摄入量，部分原因是前梨状皮质（APC）中膳食限制氨基酸（DLAA）的浓度下降。将DLAA而非非限制氨基酸注入APC，可阻断对IMB的厌食反应。据我们所知，在APC以外的区域，尚未研究过注射DLAA对缺乏DLAA的饮食（DEV）摄入量的影响。我们假设下丘脑外侧区（LH）是DLAA的一个潜在化学感应区域。我们的目标是：（1）确定将DLAA苏氨酸注入下丘脑外侧区（LH）是否会改变缺乏苏氨酸饮食（DEV）的摄入量；（2）研究将苏氨酸注入LH对苏氨酸校正饮食（COR）摄入量的剂量反应效应。在最初6小时内，以0.25和1 nmol的剂量将苏氨酸注入LH，分别使DEV摄入量增加了约26%和24%。在最初12小时内的任何时候，苏氨酸（0.25、2.5 nmol）均未改变COR的摄入量。我们的研究结果表明：（1）LH与APC一起，可能作为必需氨基酸的化学感应脑区；（2）APC和LH都是参与对氨基酸失衡饮食短期厌食反应的回路的一部分。
