Maeda S
Department of Oral physiology, Kagoshima University Dental School.
Nihon Seirigaku Zasshi. 1990;52(3):67-83.
In order to clarify developmental changing of gustatory system, 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.
为了阐明味觉系统的发育变化，在大鼠身上进行了组织学和电生理实验。对由鼓索神经支配的舌尖进行组织学检查发现，在出生后1周观察到的所有味蕾中，有 taste pore 的成熟味蕾比例仅为9%，而在3周龄时为81.3%。记录鼓索神经的综合反应发现，1周龄时有 pore 的味蕾对NaCl、HCl和盐酸奎宁的反应与成年大鼠一样，这表明这些相对年轻的味蕾在功能上对这三种刺激已经成熟。然而，1周龄时各种糖类的反应幅度与成年大鼠相比更小，在3周龄时达到最大值，然后随着年龄的增长逐渐下降。此外，不同糖类之间交叉适应实验的结果、舌部经链霉蛋白酶 - E处理的效果、对糖类的开反应和关反应之间相关性的分析表明，糖类反应的定性变化在3周龄后仍在继续。这些结果表明，在大鼠鼓索神经的出生后发育过程中，糖类味觉处理发生了功能变化。
