Shimizu Y, Tonosaki K
Department of Veterinary Physiology, Faculty of Agriculture, Gifu University, Gifu 501-1193, Japan.
Am J Physiol. 1999 Aug;277(2):R368-73. doi: 10.1152/ajpregu.1999.277.2.R368.
We studied the effects of cold ambient temperature on chorda tympani nerve responses to taste stimuli such as sucrose, NaCl, quinine HCl (QHCl), and HCl in rats. The electrophysiological recordings of the whole chorda tympani nerves from control (22 degrees C) and cold-exposed (4 degrees C) rats revealed that the responses to sucrose, HCl, and QHCl were unaffected by cold exposure. In contrast, the nerve responses to NaCl were enhanced time dependently, reaching a maximum 7-14 days after cold exposure. Responses to sodium acetate were likewise elevated as they were to NaCl, whereas those to KCl were unchanged after cold exposure. In addition, the residual NaCl responses after lingual application of the sodium-channel blocker amiloride in cold-exposed rats were similar to those in control animals. It is thus most likely that cold exposure potentiates the chorda tympani nerve responses to Na(+), but not to Cl(-). Behavioral studies with the two-bottle preference test showed that the cold-exposed rats refused to drink NaCl solutions at 0.05 and 0.1 M, the concentrations being preferred by control animals. These results suggest that the ambient temperature influences taste cell function, and that the enhanced NaCl response of the chorda tympani nerve is related to the avoidance of NaCl intake under cold environment.
我们研究了寒冷环境温度对大鼠鼓索神经对蔗糖、氯化钠、盐酸奎宁（QHCl）和盐酸等味觉刺激反应的影响。对来自对照（22摄氏度）和冷暴露（4摄氏度）大鼠的整个鼓索神经进行电生理记录发现，对蔗糖、盐酸和QHCl的反应不受冷暴露影响。相比之下，对氯化钠的神经反应随时间增强，在冷暴露后7 - 14天达到最大值。对醋酸钠的反应与对氯化钠的反应同样升高，而对氯化钾的反应在冷暴露后未改变。此外，在冷暴露大鼠舌部应用钠通道阻滞剂阿米洛利后，其对氯化钠的残余反应与对照动物相似。因此，极有可能是冷暴露增强了鼓索神经对Na⁺而非Cl⁻的反应。用双瓶偏好试验进行的行为学研究表明，冷暴露大鼠拒绝饮用0.05 M和0.1 M的氯化钠溶液，而对照动物偏好这些浓度。这些结果表明环境温度会影响味觉细胞功能，并且鼓索神经对氯化钠反应的增强与在寒冷环境下避免摄入氯化钠有关。
