Effects of gastric distension and infusion of umami and bitter taste stimuli on vagal afferent activity.
Effects of gastric distension and infusion of umami and bitter taste stimuli on vagal afferent activity.
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胃扩张和输注鲜味和苦味刺激对迷走神经传入活动的影响。
DOI：
10.1016/j.brainres.2011.08.057
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发表时间：
2011
期刊：
影响因子：
2.9
通讯作者：
Still,Liz
中科院分区：
文献类型：
--
作者：
Horn,CharlesC;Murat,Chloe;Rosazza,Matthew;Still,Liz
直到最近，从胃到大脑的感觉神经通路被认为是检测膨胀的，在营养信号中几乎没有发挥作用。新的数据已经挑战了这一观点，包括关于胃肠道中味觉受体的存在以及谷氨酸注入胃中刺激多单位迷走神经传入活动的报告。然而，评估这些化学感受效应是困难的，因为胃灌注通常引起扩张相关的迷走神经传入反应。在本研究中，我们记录了大鼠胃迷走神经传入活动，以研究通过调节输注速率和打开或关闭胃中的引流口，鲜味（谷氨酸盐，150 mM）和苦味（地那铵，10 mM）反应可以与扩张反应分离的可能性。缓慢输注生理盐水（5ml，2分钟，开放端口）对迷走神经活动没有显着影响。使用相同的输注速率，谷氨酸盐或地那铵溶液对迷走神经传入活动产生很小或没有影响。为了重现先前显示扩张和谷氨酸反应的报告，我们通过关闭出口端口产生扩张反应。在这种情况下，对谷氨酸或地那铵输注的反应与生理盐水相似。总之，我们发现胃内注入谷氨酸或地那铵对胃迷走神经传入活动的影响很小或没有影响，而胃迷走神经传入活动可以与扩张反应区分开来。目前的结果表明，对鲜味或苦味刺激的敏感性不是胃迷走神经传入纤维的共同特性。
Until recently, sensory nerve pathways from the stomach to the brain were thought to detect distension and play little role in nutritional signaling. Newer data have challenged this view, including reports on the presence of taste receptors in the gastrointestinal lumen and the stimulation of multi-unit vagal afferent activity by glutamate infusions into the stomach. However, assessing these chemosensory effects is difficult because gastric infusions typically evoke a distension-related vagal afferent response. In the current study, we recorded gastric vagal afferent activity in the rat to investigate the possibility that umami (glutamate, 150mM) and bitter (denatonium, 10mM) responses could be dissociated from distension responses by adjusting the infusion rate and opening or closing the drainage port in the stomach. Slow infusions of saline (5ml over 2min, open port) produced no significant effects on vagal activity. Using the same infusion rate, glutamate or denatonium solutions produced little or no effects on vagal afferent activity. In an attempt to reproduce a prior report that showed distention and glutamate responses, we produced a distension response by closing the exit port. Under this condition, response to the infusion of glutamate or denatonium was similar to saline. In summary, we found little or no effect of gastric infusion of glutamate or denatonium on gastric vagal afferent activity that could be distinguished from distension responses. The current results suggest that sensitivity to umami or bitter stimuli is not a common property of gastric vagal afferent fibers.