Kelley A E, Swanson C J
Dept. of Psychiatry, University of Wisconsin-Madison Medical School, 53719, USA.
Behav Brain Res. 1997 Dec;89(1-2):107-13. doi: 10.1016/s0166-4328(97)00054-5.
The corticostriatal pathway is believed to utilize the excitatory amino acid glutamate as its transmitter, and the striatum contains high levels of all glutamate receptor subtypes. It has recently been demonstrated that blockade of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainate glutamate receptors in the medial part of the accumbens, corresponding to the medial shell subregion, results in a pronounced feeding response. In order to more precisely localize this response, a microinfusion mapping study was conducted. Bilateral microinfusions of 6,7-dinitroquinoxaline-2,3-dione (DNQX, 0, 50, 250, 750 ng/0.5 microl), an antagonist that blocks AMPA and kainate receptors, were carried out in eight striatal subregions in different groups of animals. In non-deprived rats, food intake (normal chow), feeding duration, and several other behavioral measures were assessed during a 30 min test session. DNQX significantly and potently enhanced food intake when injected into the accumbens shell, but not into any other region examined, including accumbens core, anterior dorsal, posterior dorsal, ventromedial, dorsomedial, and ventrolateral striatum. The most sensitive site within the accumbens was found to be the posterior aspects of the shell, in which the lowest dose (50 ng DNQX) augmented feeding. These results suggest that a circumscribed region within the nucleus accumbens has a unique role in the control of feeding. It is postulated that removal of tonic excitatory inputs to this region with DNQX results in disinhibition of brain circuits critical for ingestive behavior.
皮质纹状体通路被认为利用兴奋性氨基酸谷氨酸作为其神经递质，并且纹状体含有所有谷氨酸受体亚型的高水平表达。最近有研究表明，阻断伏隔核内侧部分（对应于内侧壳亚区）的α-氨基-3-羟基-5-甲基异恶唑-4-丙酸（AMPA）和海人藻酸谷氨酸受体，会导致明显的进食反应。为了更精确地定位这种反应，进行了一项微量注射定位研究。在不同组动物的八个纹状体亚区进行双侧微量注射6,7-二硝基喹喔啉-2,3-二酮（DNQX，0、50、250、750 ng/0.5微升），这是一种阻断AMPA和海人藻酸受体的拮抗剂。在非饥饿大鼠中，在30分钟的测试期间评估食物摄入量（正常食物）、进食持续时间和其他几种行为指标。当将DNQX注射到伏隔核壳时，会显著且有力地增加食物摄入量，但注射到任何其他检查区域（包括伏隔核核心、前背侧、后背侧、腹内侧、背内侧和腹外侧纹状体）时则不会。发现伏隔核内最敏感的部位是壳的后部，其中最低剂量（50 ng DNQX）就会增加进食量。这些结果表明，伏隔核内的一个特定区域在进食控制中具有独特作用。据推测，用DNQX去除该区域的紧张性兴奋性输入会导致对摄食行为至关重要的脑回路去抑制。
