Flavor preferences conditioned by post-oral infusion of monosodium glutamate in rats
Flavor preferences conditioned by post-oral infusion of monosodium glutamate in rats
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DOI：
10.1016/j.physbeh.2011.05.013
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发表时间：
2011-09-01
影响因子：
2.9
通讯作者：
Sclafani, Anthony
中科院分区：
文献类型：
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作者：
Ackroff, Karen;Sclafani, Anthony
谷氨酸钠 (MSG) 是典型的鲜味来源，可以增强人类和啮齿动物对相关风味的偏好。尽管味精风味偏好归因于其味道，但迷走神经介导的口腔后检测也已得到证实。最近的研究表明，限水的大鼠对某种味道与大鼠胃内 (IC) 输注 60 mM 味精产生了偏好。本研究通过比较限制水和食物的大鼠中基于味精的风味调节并测试风味偏好的持久性来扩展这项工作。带有 IC 导管的大鼠每天饮用 30 分钟的调味溶液，并配以体积匹配的输注 01 60 mM 味精或水。进行了两个训练/测试周期，每个周期有八次一瓶训练课程，然后是两次无输液的两瓶偏好测试。食物和水限制组对味精配对风味表现出相似的偏好。当第二个周期后继续进行非强化测试时，限制食物的组在三个为期两天的测试中保持其偏好，但限制水的老鼠失去了他们的偏好。其他食物限制的大鼠学会了更喜欢与十二指肠内输注搭配的风味，这表明不需要味精刺激胃。第三个实验表明，在味精 IC 输液中添加 2 mM 核苷酸肌苷单磷酸并没有显着增强风味调理效果。由于基于味精的风味偏好可以通过绕过胃的输注来获得，因此检测味精强化的部位可能是肠道。 (C) 2011 Elsevier Inc. 保留所有权利。
Monosodium glutamate (MSG), the prototypical umami source, can enhance preference for associated flavors in humans and rodents. Although MSG flavor preference has been attributed to its taste, vagally-mediated post-oral detection has also been demonstrated. Recent studies showed that water-restricted rats acquired a preference for a flavor paired with intragastric (IC) infusion of 60 mM MSG in rats. The present study extends this work by comparing MSG-based flavor conditioning in water- and food-restricted rats and testing the persistence of flavor preferences. Rats with IC catheters drank flavored solutions paired with volume-matched infusions 01 60 mM MSG or water in daily 30-min sessions. Two training/test cycles were conducted, each with eight one-bottle training sessions followed by two two-bottle preference tests without infusions. Food- and water-restricted groups displayed similar preferences for the MSG-paired flavor. When non-reinforced testing was continued after the second cycle, the food-restricted group sustained its preference across three 2-day tests, but water-restricted rats lost their preference. Other food-restricted rats learned to prefer a flavor paired with intraduodenal infusion, indicating that gastric stimulation by MSG is not required. A third experiment showed that adding 2 mM of the nucleotide inosine monophosphate to the IC infusion of MSG did not significantly enhance flavor conditioning. Because MSG-based flavor preferences can be obtained with infusions that bypass the stomach, the site for detecting MSG reinforcement may be intestinal. (C) 2011 Elsevier Inc. All rights reserved.