Smith D V, Ossebaard C A
Department of Anatomy, University of Maryland School of Medicine, Baltimore 21201, USA.
Physiol Behav. 1995 Apr;57(4):773-7. doi: 10.1016/0031-9384(94)00329-7.
The transduction of Na+ salts has been shown in many species to be mediated in part by an epithelial ion channel on the apical surface of the taste receptor cell membrane, which is blockable by the diuretic amiloride. In addition to this apical ion channel, Na+ is also transduced via a paracellular pathway, which is not sensitive to amiloride. There are significant species differences in the contribution of the amiloride-sensitive pathway to Na+ transduction. Previous human psychophysical studies have reported conflicting results on the effects of amiloride in suppressing the intensity of NaCl. In general, these studies used amiloride doses that were much higher than those showing clear suppressive effects in electrophysiological studies in other species. In the present experiment, we used direct magnitude scaling of the intensities of five NaCl concentrations flowed over the anterior portion of the tongue to determine the effects of amiloride treatment at lower doses. NaCl was presented after adaptation of the tongue to water or mixed with and presented after adaptation to 10, 50, or 100 microM amiloride-HCl. Subjects estimated the intensity of NaCl and of these concentrations of amiloride in each treatment condition using magnitude estimation with a 0.1 M NaCl modulus presented following a water rinse prior to each session. Results showed that amiloride had a significant suppressive effect on the perceived intensity of NaCl, with a similar effect seen at all three amiloride doses. The psychophysical function after amiloride showed a parallel shift to the right. The average suppression over all NaCl concentrations was 21%.(ABSTRACT TRUNCATED AT 250 WORDS)
在许多物种中，已证明钠盐的转导部分是由味觉受体细胞膜顶端表面的上皮离子通道介导的，该通道可被利尿药氨氯吡咪阻断。除了这种顶端离子通道外，Na⁺ 也通过细胞旁途径进行转导，该途径对氨氯吡咪不敏感。氨氯吡咪敏感途径对 Na⁺ 转导的贡献存在显著的物种差异。先前的人体心理物理学研究报告了关于氨氯吡咪抑制 NaCl 强度效果的相互矛盾的结果。一般来说，这些研究使用的氨氯吡咪剂量远高于在其他物种的电生理研究中显示出明显抑制作用的剂量。在本实验中，我们使用直接量级缩放法来确定五种 NaCl 浓度流经舌前部时的强度，以确定较低剂量氨氯吡咪处理的效果。在舌头适应水后或与 10、50 或 100 microM 氨氯吡咪 - HCl 混合并在适应后呈现 NaCl。受试者在每次实验前用水冲洗后，使用以 0.1 M NaCl 模量进行量级估计的方法，估计每种处理条件下 NaCl 和这些氨氯吡咪浓度的强度。结果表明，氨氯吡咪对 NaCl 的感知强度有显著抑制作用，在所有三种氨氯吡咪剂量下效果相似。氨氯吡咪处理后的心理物理学函数显示向右平行移动。所有 NaCl 浓度的平均抑制率为 21%。（摘要截断于 250 字）
