Liang Nu-Chu, Hajnal Andras, Norgren Ralph
Dept. of Neural and Behavioral Sciences, College of Medicine, The Pennsylvania State Univ., 500 Univ. Drive, Hershey, PA 17033, USA.
Am J Physiol Regul Integr Comp Physiol. 2006 Nov;291(5):R1236-9. doi: 10.1152/ajpregu.00226.2006. Epub 2006 Jun 8.
Both real and sham feeding of sucrose increase dopamine (DA) overflow in the nucleus accumbens (NAc). Fat is another constituent of foods that is inherently preferred by humans and rodents. We examined the affect of sham feeding corn oil in rats that were food and water deprived overnight. Rats were implanted with guide cannulas aimed at the NAc, as well as gastric fistulas. On alternate days, they were trained to sham lick 100% corn oil or distilled water (dH2O) for 20 min in the morning. Twenty-minute microdialysis samples were taken before, during, and after sham licking. DA and monoamines were analyzed by reverse-phase HPLC with coulometric detection. The results show that DA release in the NAc was significantly increased during sham licking of corn oil compared with the prior baseline (157.5+/-18.8%, n=12). During sham licking of dH2O, DA release in the NAc was not changed (93.0+/-4.0%, n=15). This experiment demonstrates that sham feeding of corn oil releases accumbens DA in a manner similar to ingestion of sucrose. Although both stimuli may have an olfactory component, sucrose is a gustatory, and 100% corn oil appears to be a trigeminal stimulus. Thus these data support the hypothesis that different sensory modalities produce reward using the same or closely related substrates in the forebrain.
给予蔗糖的真饲和假饲都会增加伏隔核（NAc）中的多巴胺（DA）溢出。脂肪是食物的另一种成分，人类和啮齿动物天生就偏爱它。我们研究了对隔夜禁食禁水的大鼠进行假饲玉米油的影响。将大鼠植入针对伏隔核的引导套管以及胃瘘管。每隔一天，训练它们在早晨假舔100%玉米油或蒸馏水（dH2O）20分钟。在假舔之前、期间和之后采集20分钟的微透析样本。通过带有库仑检测的反相高效液相色谱法分析DA和单胺。结果显示，与先前的基线相比，在假舔玉米油期间伏隔核中的DA释放显著增加（157.5±18.8%，n = 12）。在假舔蒸馏水期间，伏隔核中的DA释放没有变化（93.0±4.0%，n = 15）。该实验表明，假饲玉米油以类似于摄入蔗糖的方式释放伏隔核DA。尽管两种刺激可能都有嗅觉成分，但蔗糖是味觉刺激，而100%玉米油似乎是三叉神经刺激。因此，这些数据支持了这样的假设，即不同的感觉模态在前脑中使用相同或密切相关的底物产生奖赏。
