Decrease in rat taste receptor cell intracellular pH is the proximate stimulus in sour taste transduction
Decrease in rat taste receptor cell intracellular pH is the proximate stimulus in sour taste transduction
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DOI：
10.1152/ajpcell.2001.281.3.c1005
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发表时间：
2001-09-01
影响因子：
5.5
通讯作者：
DeSimone, JA
中科院分区：
文献类型：
--
作者：
Lyall, V;Alam, RI;DeSimone, JA
味觉感受器细胞（Taste receptor cells，TRC）对酸刺激有反应，启动对酸味的感知。奇怪的是，弱酸性刺激的pH值与其酸味的感知相关性很差。围绕酸味接收的一个基本问题是酸味刺激的身份。我们测试了酸通过作为H+离子或作为未解离的分子穿透质膜并降低TRC的细胞内pH（pH（i））来诱导酸味感知的假设。我们的数据表明，味觉神经对弱酸（乙酸和CO2）的反应是独立的刺激pH值，但强烈相关的极化TRCs的细胞内酸化。味觉神经对CO2的反应是电压敏感的，并被碳酸酐酶特异性阻断剂MK-417阻断。强酸（HCl）降低含有H+进入途径的TRC亚组中的pHi。顶端膜和细胞旁分流途径都限制H+进入，使得顶端pH的大幅降低转化为生理范围内TRC pH（i）的相对较小的变化。我们得出结论，TRC pH（i）的降低是大鼠酸味转导中的最接近刺激。
Taste receptor cells (TRCs) respond to acid stimulation, initiating perception of sour taste. Paradoxically, the pH of weak acidic stimuli correlates poorly with the perception of their sourness. A fundamental issue surrounding sour taste reception is the identity of the sour stimulus. We tested the hypothesis that acids induce sour taste perception by penetrating plasma membranes as H+ ions or as undissociated molecules and decreasing the intracellular pH (pH(i)) of TRCs. Our data suggest that taste nerve responses to weak acids (acetic acid and CO2) are independent of stimulus pH but strongly correlate with the intracellular acidification of polarized TRCs. Taste nerve responses to CO2 were voltage sensitive and were blocked with MK-417, a specific blocker of carbonic anhydrase. Strong acids (HCl) decrease pHi in a subset of TRCs that contain a pathway for H+ entry. Both the apical membrane and the paracellular shunt pathway restrict H+ entry such that a large decrease in apical pH is translated into a relatively small change in TRC pH(i) within the physiological range. We conclude that a decrease in TRC pH(i) is the proximate stimulus in rat sour taste transduction.