Acid-induced responses in hamster chorda tympani and intracellular pH tracking by taste receptor cells.
Acid-induced responses in hamster chorda tympani and intracellular pH tracking by taste receptor cells.
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仓鼠鼓索中的酸诱导反应和味觉受体细胞的细胞内 pH 跟踪。
DOI：
10.1152/ajpcell.1998.275.1.c227
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
DeSimone,JA
中科院分区：
文献类型：
--
作者：
Stewart,RE;Lyall,V;Feldman,GM;Heck,GL;DeSimone,JA
盐酸和氯化钠诱导的仓鼠鼓索神经反应记录在电压钳的舌感受野。电压扰动不影响对HCl的响应。相反，对NaCl的反应减少粘膜下的阳性和增加粘膜下的负电压钳。对HCl的反应对Na+通道阻滞剂阿米洛利和苯扎米尔以及Na+/H+交换阻滞剂甲基异丁基阿米洛利（MIA）不敏感。对NaCl的反应不受MIA的影响，但被苯扎明抑制。采用显微荧光和成像技术监测2 '，7'-双（2-羧乙基）-5（6）-羧基荧光素负载后菌状乳头味觉受体细胞（TRC）的外部pH（pHo）和细胞内pH（pHi）之间的关系。TRC pHi对pHo的变化反应迅速且单调。这种反应不受Na+去除或阿米洛利，苯扎米尔，或MIA的存在。神经记录和离体TRC的数据表明，仓鼠的酸味主要传导途径与大鼠的相似。这可能涉及监测通过阿米洛利不敏感的H+跨TRC膜转运介导的TRC pH的变化。这是通过pH跟踪的环境pH的细胞监测的实例，即，响应于pHo的变化，pHi的线性变化，如已经针对颈动脉体提出的。在味觉中，H+转运位点可能集中在TRC的基底外侧膜上，因此，对酸穿过紧密连接扩散的减弱的H+浓度有反应。
HCl- and NaCl-induced hamster chorda tympani nerve responses were recorded during voltage clamp of the lingual receptive field. Voltage perturbations did not influence responses to HCl. In contrast, responses to NaCl were decreased by submucosal-positive and increased by submucosal-negative voltage clamp. Responses to HCl were insensitive to the Na+channel blockers, amiloride and benzamil, and to methylisobutylamiloride (MIA), an Na+/H+exchange blocker. Responses to NaCl were unaffected by MIA but were suppressed by benzamil. Microfluorometric and imaging techniques were used to monitor the relationship between external pH (pHo) and the intracellular pH (pHi) of fungiform papilla taste receptor cells (TRCs) following 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein loading. TRC pHiresponded rapidly and monotonically to changes in pHo. This response was unaffected by Na+removal or the presence of amiloride, benzamil, or MIA. The neural records and the data from isolated TRCs suggest that the principal transduction pathway for acid taste in hamster is similar to that in rat. This may involve the monitoring of changes in TRC pHimediated through amiloride-insensitive H+transport across TRC membranes. This is an example of cell monitoring of environmental pH through pH tracking, i.e., a linear change in pHiin response to a change in pHo, as has been proposed for carotid bodies. In taste, the H+transport sites may be concentrated on the basolateral membranes of TRCs and, therefore, are responsive to an attenuated H+concentration from diffusion of acids across the tight junctions.