Taste discrimination between NaCl and KCl is disrupted by amiloride in inbred mice with amiloride-insensitive chorda tympani nerves
Taste discrimination between NaCl and KCl is disrupted by amiloride in inbred mice with amiloride-insensitive chorda tympani nerves
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DOI：
10.1152/ajpregu.00796.2004
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发表时间：
2005-05-01
影响因子：
2.8
通讯作者：
Spector, AC
中科院分区：
文献类型：
--
作者：
Eylam, S;Spector, AC
阿米洛利敏感的盐转导通路被认为是区分啮齿动物钠盐和非钠盐的关键。在大鼠中，舌下应用阿米洛利似乎使氯化钠和氯化钾在性质上无法区分。在这项研究中，我们测试了四个品系的小鼠对盐的辨别能力。在一个品系(C57BL/6J)中，鼓索神经(CT)对氯化钠的反应被阿米洛利减弱，而在另外三个品系(BALB/cByJ、129P3/J、DBA/2J)中，它们不被减弱。在限水条件下，这些小鼠(7只小鼠/品系)在Gustometer中被训练，以舔来自一个加固喷嘴的水，以响应五舔的氯化钠，并响应于KCl[盐浓度变化(0.1-1M)，使强度无关]。然后用溶解在盐酸阿米洛利中的刺激物对小鼠进行测试，并以后者作为增强剂。每种浓度的阿米洛利(0.1-100亩M)分别在两天内使用，并设置对照组。所有四个品系的小鼠都能可靠地区分氯化钠和氯化钾。阿米洛利以剂量依赖的方式削弱了这种辨别能力。此外，在所有四个菌株中，在氯化钠试验中，阿米洛利对表现的影响似乎比在氯化钾试验中更大。因此，与基于CT记录的预测相反，所有四个菌株的辨别似乎都依赖于阿米洛利敏感的转导途径，在BALB/cByJ、129P3/J和DBA/2J(可能还有C57BL/6)的情况下，可能存在于CT以外的神经支配的味蕾中。
The amiloride-sensitive salt transduction pathway is thought to be critical for the discrimination between sodium and nonsodium salts in rodents. In rats, lingual application of amiloride appears to render NaCl qualitatively indistinguishable from KCl. In this study, we tested four strains of mice for salt discriminability. In one strain (C57BL/6J), chorda tympani nerve (CT) responses to NaCl are attenuated by amiloride, and in the other three strains (BALB/cByJ, 129P3/J, DBA/2J) they are not. Under water-restriction conditions, these mice (7 mice/strain) were trained in a gustometer to lick for water from one reinforcement spout in response to a five-lick presentation of NaCl and to lick from another in response to KCl [ salt concentration was varied (0.1-1 M) to render intensity irrelevant]. Mice were then tested with the stimuli dissolved in amiloride hydrochloride, and the latter was used as the reinforcer as well. Each concentration of amiloride (0.1-100 mu M) was used on 2 separate days with control sessions interposed. Mice from all four strains were able to discriminate NaCl from KCl reliably. Amiloride impaired this discrimination in a dose-dependent fashion. Moreover, performance on NaCl trials appeared to be more affected by amiloride than that on KCl trials in all four strains. Thus, in contrast to the predictions based on CT recordings, discrimination in all four strains appeared to depend on the amiloride-sensitive transduction pathway, which, in the case of BALB/cByJ, 129P3/J, and DBA/2J (and perhaps C57BL/6 as well), may exist in taste buds innervated by nerves other than the CT.