Schiffman S S, Suggs M S, Cragoe E J, Erickson R P
Department of Psychiatry, Duke University, Durham, NC 27706.
Physiol Behav. 1990 Mar;47(3):455-9. doi: 10.1016/0031-9384(90)90108-g.
The Na+ transport inhibitor amiloride blocks taste responses to NaCl by 60-70%. The purpose of the present study was to determine if greater inhibition could be achieved with three potent amiloride analogs that are specific for the epithelial Na+ channel: phenamil, 2',4'-dimethylbenzamil, and 3',4'-dichlorobenzamil. Application of phenamil (100 microM) to the anterior tongue blocked integrated responses to NaCl from the chorda tympani nerve by 98.04%, but had no significant effect on sucrose or NH4Cl. This finding suggests that the epithelial Na+ channel alone transduces the taste of NaCl in gerbil. The residual 30-40% of the response that is not blocked by amiloride can simply be explained by the fact that amiloride is less potent than phenamil. On average, 100 microM phenamil blocked responses to Na+ salts with a variety of anions by 94.2%; 100 microM 2',4'-dimethylbenzamil, by 89.83%; and 100 microM 3',4'-dichlorobenzamil, by 72.56%. Small residual responses to salts of glutamate and phosphate were not eliminated by the amiloride analogs; this suggests that other transduction mechanisms may account for a small portion of taste responses for these salts in the gerbil.
钠离子转运抑制剂氨氯吡咪可使对氯化钠的味觉反应降低60 - 70%。本研究的目的是确定三种对上皮钠离子通道具有特异性的强效氨氯吡咪类似物（苯甲咪、2',4'-二甲基苯甲咪和3',4'-二氯苯甲咪）是否能实现更强的抑制作用。将苯甲咪（100微摩尔）应用于舌前部，可使鼓索神经对氯化钠的综合反应降低98.04%，但对蔗糖或氯化铵没有显著影响。这一发现表明，在沙鼠中，仅上皮钠离子通道就能传导氯化钠的味觉。氨氯吡咪未阻断的30 - 40%的残余反应，可简单地解释为氨氯吡咪的效力低于苯甲咪。平均而言，100微摩尔苯甲咪可使对含有各种阴离子的钠盐的反应降低94.2%；100微摩尔2',4'-二甲基苯甲咪可使其降低89.83%；100微摩尔3',4'-二氯苯甲咪可使其降低72.56%。谷氨酸盐和磷酸盐的盐类的微小残余反应未被氨氯吡咪类似物消除；这表明其他转导机制可能在沙鼠中对这些盐类的味觉反应中占一小部分。
