Dessirier J M, O'Mahony M, Iodi-Carstens M, Yao E, Carstens E
Section of Neurobiology, Physiology, and Behavior, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA.
Physiol Behav. 2001 Feb;72(3):317-24. doi: 10.1016/s0031-9384(00)00412-1.
Psychophysical methods were used to investigate the irritant sensory properties of concentrated NaCl. The first experiment investigated potential sensitization and desensitization properties. Subjects rated the intensity of the irritation elicited by 10 successive applications of 5 M NaCl on one side of the dorsal surface of the tongue. The mean irritant sensation increased significantly across trials, consistent with sensitization. To test for self- and cross-desensitization effects of unilateral sequential stimulation with NaCl followed by a 10-min rest period, either 5 M NaCl or 10 microM capsaicin was applied bilaterally. In a two-alternative forced-choice (2-AFC) test, subjects indicated which side of the tongue had a stronger irritant sensation. They also rated the intensity of irritation on each side separately. When NaCl was applied bilaterally, the side not previously receiving NaCl was chosen as stronger by a significant majority of subjects and was given significantly higher intensity ratings, consistent with self-desensitization. In contrast, when capsaicin was applied bilaterally, the side that had previously received sequential NaCl was perceived as having a significantly more intense irritation, consistent with cross-sensitization. In a second experiment, the effect of amiloride on NaCl-evoked irritation was studied. One side of the tongue was treated with 1 mM amiloride, after which 5 M NaCl was applied bilaterally and subjects performed the same 2-AFC and rating procedures. Since amiloride significantly reduced the intensity of the irritant sensation, the contribution of amiloride-sensitive ionic currents or the Na+/H+ exchange pump (NHE) are suggested as possible transduction mechanisms in lingual nociceptors mediating NaCl-evoked oral irritation.
采用心理物理学方法研究了浓缩氯化钠的刺激性感觉特性。第一个实验研究了潜在的致敏和脱敏特性。受试者对在舌背一侧连续10次施用5M氯化钠所引起的刺激强度进行评分。在多次试验中，平均刺激感觉显著增加，这与致敏作用一致。为了测试用氯化钠进行单侧顺序刺激并随后休息10分钟后的自我和交叉脱敏效果，双侧施用5M氯化钠或10μM辣椒素。在二项迫选（2-AFC）测试中，受试者指出舌头的哪一侧有更强的刺激感觉。他们还分别对每一侧的刺激强度进行评分。当双侧施用氯化钠时，绝大多数受试者选择未预先接受氯化钠的一侧为更强的一侧，并且该侧的强度评分显著更高，这与自我脱敏一致。相反，当双侧施用辣椒素时，先前接受过顺序氯化钠刺激的一侧被认为具有明显更强的刺激，这与交叉致敏一致。在第二个实验中，研究了阿米洛利对氯化钠诱发刺激的影响。舌头的一侧用1mM阿米洛利处理，之后双侧施用5M氯化钠，受试者进行相同的2-AFC和评分程序。由于阿米洛利显著降低了刺激感觉的强度，提示阿米洛利敏感的离子电流或钠/氢交换泵（NHE）可能是介导氯化钠诱发口腔刺激的舌伤害感受器中的转导机制。
