Simon S A, Robb R, Schiffman S S
Department of Physiology, Duke University Medical Center, Durham, NC 27710.
Pharmacol Biochem Behav. 1988 Feb;29(2):257-67. doi: 10.1016/0091-3057(88)90154-2.
Measurements of ion transport across isolated lingual epithelium of rat were correlated with electrophysiological recordings from taste nerves. At hyperosmotic concentrations of NaCl, sodium ions enter the mucosal membrane of the isolated epithelium partially through an amiloride-inhibitable pathway and exit the serosal membrane through a Na+-K+-ATPase. At hyposmotic concentrations of KCl, potassium ions enter the mucosal membrane through a K+ pathway that is inhibited by 4-aminopyridine and exit at the serosal membrane through a K+ pathway that is inhibited by BaCl2. The inhibition of sodium transport by amiloride and potassium transport by 4-aminopyridine is consistent with previously published electrophysiological recordings from the chorda tympani nerve bundle (CT) and recordings from nucleus of the solitary tract (NST) obtained here. The responses to NaCl are greater than the responses to KCl at equimolar concentrations over the entire concentration range both in epithelial and neural measurements. At hyposmotic concentrations of NaCl the epithelial responses include inward sodium and outward chloride components. Isolated rat tongue is only slightly stimulated by D-glucose or sucrose as are the CT and NTS responses. These data suggest that events in taste transduction can be understood, in part, by measuring the epithelial responses of isolated rat tongue.
对大鼠离体舌上皮离子转运的测量结果与味觉神经的电生理记录相关。在高渗浓度的氯化钠溶液中，钠离子部分通过氨氯地平可抑制的途径进入离体上皮的黏膜膜，并通过钠钾ATP酶从浆膜膜排出。在低渗浓度的氯化钾溶液中，钾离子通过被4-氨基吡啶抑制的钾离子通道进入黏膜膜，并通过被氯化钡抑制的钾离子通道从浆膜膜排出。氨氯地平对钠转运的抑制作用以及4-氨基吡啶对钾转运的抑制作用与先前发表的鼓索神经束（CT）的电生理记录以及此处获得的孤束核（NST）的记录一致。在整个浓度范围内，等摩尔浓度下，上皮和神经测量中对氯化钠的反应均大于对氯化钾的反应。在低渗浓度的氯化钠溶液中，上皮反应包括内向的钠成分和外向的氯成分。分离的大鼠舌对D-葡萄糖或蔗糖的刺激很轻微，CT和NTS的反应也是如此。这些数据表明，通过测量分离的大鼠舌的上皮反应，部分可以理解味觉转导中的事件。
