Hill D L, Phillips L M
Department of Psychology, University of Virginia, Charlottesville 22903-2477.
J Neurosci. 1994 May;14(5 Pt 1):2904-10. doi: 10.1523/JNEUROSCI.14-05-02904.1994.
Unilateral chorda tympani nerve sectioning was combined with institution of a sodium-restricted diet in adult rats to determine the role that environment has on the functional properties of regenerating taste receptor cells. Rats receiving chorda tympani sectioning but no dietary manipulation (cut controls) and rats receiving only the dietary manipulation (diet controls) had normal responses to a concentration series of NaCl, sodium acetate (NaAc), and NH4Cl. However, responses from the regenerated nerve in NaCl-restricted rats (40-120 d postsectioning) to NaCl and NaAc were reduced by as much as 30% compared to controls, indicating that regenerating taste receptors are influenced by environmental (dietary) factors. Responses to NH4Cl were normal; therefore, the effect appears specific to sodium salts. Surprisingly, in the same rats, NaCl responses from the contralateral, intact chorda tympani were up to 40% greater than controls. Thus, in the same rat, there was over a twofold difference in sodium responses between the right and left chorda tympani nerves. A study of the time course of the functional alterations in the intact nerve revealed that responses to NaCl were extremely low immediately following sectioning (about 20% of the normal response), and then increased monotonically during the following 50 d until relative response magnitudes became supersensitive. This function occurred even when the cut chorda tympani was prevented from reinnervating lingual epithelia, demonstrating that events related to regeneration do not play a role in the functional properties of the contralateral side of the tongue.(ABSTRACT TRUNCATED AT 250 WORDS)
在成年大鼠中，将单侧鼓索神经切断与限制钠饮食相结合，以确定环境对再生味觉受体细胞功能特性的作用。接受鼓索神经切断但未进行饮食干预的大鼠（切断对照组）和仅接受饮食干预的大鼠（饮食对照组）对一系列浓度的氯化钠、醋酸钠（NaAc）和氯化铵有正常反应。然而，与对照组相比，限制氯化钠饮食的大鼠（切断后40 - 120天）再生神经对氯化钠和醋酸钠的反应降低了多达30%，这表明再生味觉受体受环境（饮食）因素影响。对氯化铵的反应正常；因此，这种影响似乎对钠盐具有特异性。令人惊讶的是，在同一只大鼠中，对侧完整鼓索神经对氯化钠的反应比对照组高40%。因此，在同一只大鼠中，左右鼓索神经对钠的反应相差两倍多。对完整神经功能改变的时间进程研究表明，切断后立即对氯化钠的反应极低（约为正常反应的20%），然后在接下来的50天内单调增加，直到相对反应幅度变得超敏。即使阻止切断的鼓索神经重新支配舌上皮，这种功能仍会发生，这表明与再生相关的事件对舌对侧的功能特性没有作用。（摘要截断于250字）
