Responses to Apical and Basolateral Application of Glutamate in Mouse Fungiform Taste Cells with Action Potentials
Responses to Apical and Basolateral Application of Glutamate in Mouse Fungiform Taste Cells with Action Potentials
复制标题
DOI：
10.1007/s10571-011-9702-5
复制
发表时间：
2011-10-01
影响因子：
4
通讯作者：
Yoshida, Ryusuke
中科院分区：
文献类型：
--
作者：
Niki, Mayu;Takai, Shingo;Yoshida, Ryusuke
在味蕾细胞中，谷氨酸可能会引发两种类型的反应，一种是鲜味反应，另一种是神经递质反应。谷氨酸作用于味觉细胞的顶膜可引起味觉反应，而谷氨酸作用于味觉细胞的基侧膜可能起到神经递质的作用。通过对味觉细胞顶膜或基底侧膜的限制性刺激，我们分别检测了味觉细胞对谷氨酸刺激的反应。谷氨酸单钠(MSG，0.3M)的顶端应用增加了一些小鼠真菌样味觉细胞的放电频率，从而诱发了动作电位。这些细胞用其他基本味道化合物--氯化钠(咸的)、糖精(甜的)、盐酸(酸的)和奎宁(苦的)进行测试。味精敏感的味觉细胞可分为甜味最佳(S型)、味精最佳(M型)和氯化钠或其他电解质最佳(N或E/H型)细胞。此外，根据味精与5‘-磷酸肌苷的协同作用，S和M型可分为两个亚型(S1、M1有协同作用；S2、M2无协同作用)。谷氨酸(100mM)对味觉细胞的平均自发放电频率几乎没有影响。然而，在被测试的味觉细胞中，大约10%的细胞在基础侧向应用谷氨酸后，自发放电率(>；平均值+2标准差)显示出一过性的增加。这些结果表明，存在多种类型的手指敏感的味觉细胞，并在味觉细胞亚群的基底外侧膜上存在谷氨酸受体(S)。
In taste bud cells, glutamate may elicit two types of responses, as an umami tastant and as a neurotransmitter. Glutamate applied to apical membrane of taste cells would elicit taste responses whereas glutamate applied to basolateral membrane may act as a neurotransmitter. Using restricted stimulation to apical or basolateral membrane of taste cells, we examined responses of taste cells to glutamate stimulation, separately. Apical application of monosodium glutamate (MSG, 0.3 M) increased firing frequency in some of mouse fungiform taste cells that evoked action potentials. These cells were tested with other basic taste compounds, NaCl (salty), saccharin (sweet), HCl (sour), and quinine (bitter). MSG-sensitive taste cells could be classified into sweet-best (S-type), MSG-best (M-type), and NaCl or other electrolytes-best (N- or E/H-type) cells. Furthermore, S- and M-type could be classified into two sub-types according to the synergistic effect between MSG and inosine-5'-monophosphate (S1, M1 with synergism; S2, M2 without synergism). Basolateral application of glutamate (100 mu M) had almost no effect on the mean spontaneous firing rates in taste cells. However, about 10% of taste cells tested showed transient increases in spontaneous firing rates (> mean + 2 standard deviation) after basolateral application of glutamate. These results suggest the existence of multiple types of umami-sensitive taste cells and the existence of glutamate receptor(s) on the basolateral membrane of a subset of taste cells.