Changes of gustatory system through life time

味觉系统的终身变化为了阐明味觉系统的终身变化，我们对大鼠进行了组织学和电生理学实验。对鼓索神经支配的舌前部进行组织学观察，结果表明：生后1周龄时，具有味孔的成熟味蕾仅占全部味蕾的9%，3周龄时为81.3%。记录鼓索神经的综合反应显示，1周龄时具有孔的味蕾对NaCl、HCl和奎宁-HCl的反应与成年大鼠一样，这表明这些相对年轻的味蕾对这三种刺激的功能已经成熟。然而，与成年大鼠相比，1周龄时对各种糖的反应幅度较小，在3周龄时达到最大值，随后随日龄的增加逐渐下降。此外，来自不同糖之间的交叉适应实验、链霉蛋白酶-E处理舌头的效果、对糖的开启响应和关闭响应之间的相关性分析的结果表明，糖响应的质的变化在3周龄后继续。这些结果表明，功能的变化发生在味觉处理糖在出生后的发展过程中，在大鼠鼓索神经。

CHANGES OF GUSTATORY SYSTEM THROUGH LIFE TIME.In order to clarify changes of gustatory system through life time, histological and electrophysiological experiments were performed in the rat. Histological examination on the anterior tongue innervated by chorda tympani nerve showed that the ratio of matured taste buds which possess a taste pore were only 9% of all taste buds observed at 1 week of postnatal age, and 81.3% at 3 weeks of age. Recording integrated responses from the chorda tympani nerve reveals that taste buds with a pore at 1 week of age responded to NaCl, HCl, and quinine-HCl as well as in adult rats, which suggests that these relatively young taste buds are matured functionally for these three stimuli.However, the response magnitudes for various sugars at 1 week of age were smaller compared to those in the adult rat, reached to the maximum at 3 weeks of age, then decreased gradually with age. Also, results from the experiment of cross-adaptation among different sugars, effects of pronase-E treatment of the tongue, analysis of correlation between on- and off-responses to sugars, showed that qualitative changes for sugar responses continues after 3 weeks of age. These results suggest that functional changes occur in the gustatory processing of sugars during postnatal development in the rat chorda tympani nerve.