Baylis L L, Rolls E T
Department of Experimental Psychology, University of Oxford, England.
Physiol Behav. 1991 May;49(5):973-9. doi: 10.1016/0031-9384(91)90210-f.
In order to investigate the neural encoding of glutamate in the primate, recordings were made from 190 taste responsive neurons in the primary taste cortex and adjoining orbitofrontal cortex taste area in macaques. Single neurons were found that were tuned to respond best to glutamate (umami taste), just as other cells were found with best responses to glucose (sweet), sodium chloride (salty), HCl (sour), and quinine HCl (bitter). Across the population of neurons, the responsiveness to glutamate was poorly correlated with the responsiveness to NaCl, so that the representation of glutamate was clearly different from that of NaCl. Further, the representation of glutamate was shown to be approximately as different from each of the other four tastants as they are from each other, as shown by multidimensional scaling and cluster analysis. Moreover, it was found that glutamate is approximately as well represented in terms of mean evoked neural activity and the number of cells with best responses to it as the other four stimuli, glucose, NaCl, HCl and quinine. It is concluded that in primate taste cortical areas, glutamate, which produces umami taste in humans, is approximately as well represented as are the tastes produced by: glucose (sweet), NaCl (salty), HCl (sour) and quinine HCl (sour).
为了研究灵长类动物中谷氨酸的神经编码，研究人员在猕猴的初级味觉皮层和相邻的眶额皮层味觉区域对190个味觉反应神经元进行了记录。发现了一些单个神经元，它们对谷氨酸（鲜味）反应最佳，就像发现其他细胞对葡萄糖（甜味）、氯化钠（咸味）、盐酸（酸味）和盐酸奎宁（苦味）反应最佳一样。在整个神经元群体中，对谷氨酸的反应性与对氯化钠的反应性相关性很差，因此谷氨酸的表征与氯化钠的表征明显不同。此外，多维标度和聚类分析表明，谷氨酸的表征与其他四种味觉物质中的每一种的差异大致相同，就像它们彼此之间的差异一样。此外，研究发现，就平均诱发神经活动和对其反应最佳的细胞数量而言，谷氨酸的表征与其他四种刺激物（葡萄糖、氯化钠、盐酸和奎宁）大致相同。研究得出结论，在灵长类动物的味觉皮层区域，在人类中产生鲜味的谷氨酸，其表征与葡萄糖（甜味）、氯化钠（咸味）、盐酸（酸味）和盐酸奎宁（酸味）产生的味觉大致相同。
