Morphological and Electrophysiological Studies on the Formation of the Neural Tract and the Function in the Taste of Frog Chimerae.

1.在各种琼脂浸泡的味觉刺激中，爪蟾（X。borealis和X. laevis）接受L-Pro、L-Trp和L-Val，而拒绝L-Arg、奎宁和HCl。一般情况下，X.北方花比北方花更活跃，对这些味觉刺激的阈值更低。光滑。通过将一个物种的半个胚胎与另一个物种的半个胚胎连接而产生的黑猩猩的摄食行为与X相似。laevis，无论X. borealis. 2.用丽春红S染色法计算出的味蕾在上颚约300个，口底约200个，密集分布在内唇和内唇周围。这两个物种和嵌合体的味蕾的数量和位置相似。用奎纳克林染色证实了味细胞起源于X.北极星位于同侧的嵌合体中。然而，其对侧位置的范围尚不清楚。用HRP法对舌咽神经进行形态学追踪，结果显示，延髓内有中枢味觉神经元分布于同侧.两种舌咽神经对60种味觉刺激的反应差异主要表现在：（1）L-Phe在所有浓度范围内的反应差异显著，而L-和D-Trp、L-和D-Tyr在一定浓度范围内的反应差异显著。(2)对奎宁和士的宁的反应的差异在很宽的浓度范围内得到证实。(3)在各种核苷酸和核苷中，只有腺苷在X中产生相当大的响应。borealis，而X.光滑。以这些物质为关键刺激物，证明了黑猩猩舌咽神经在青年期引起种特异性反应，但倾向于产生X射线反应。随着年龄的增长，

1. Of various agar-soaked gustatory stimuli, Xenopus (X. borealis and X. laevis) accepted L-Pro, L-Trp, and L-Val, while rejected L-Arg, quinine, and HCl. In general, X. borealis was more active and had lower thresholds for these gustatory stimuli than X. laevis. Feeding behavior of chimerae, which were produced by joining a half of an embryo of one species with that of another species, revealed similar behavior to X. laevis, regardless of the location of a half of an embryo of X. borealis.2. Taste buds calculated by staining with Ponceau S were about 300 on the palate, and about 200 on the floor of the mouth, and densely distributed on the inner lip and around the internal nostril. Both the number and location of the taste bud were similar among the two species and chimera. It was confirmed by staining with quinacrine that taste cells originated from an embryo of X. borealis are located ipsilaterally in chimerae. The extent of their contralateral location, however, were left unclear. Morphological tracing of glossopharyngeal nerves with HRP techniques showed that central gustatory neurons are distributed ipsilaterally in the medulla oblongata.3. Major differences in gustatory responses of the glossopharyngeal nerves to 60 gustatory stimuli between the two species were as follow: (1) L-Phe caused significant differences in responses over all concentrations tested, whereas L- and D-Trp, and L- and D-Tyr produced prominent differences in responses within a given concentration range. (2) differences in responses to quinine and strychnine were demonstrated throughout a wide concentration range. (3) among various nucleotides and nucleosides only adenosine produced fairly large responses in X. borealis, but very small responses in X. laevis. It was demonstrated using these substances as key stimuli that glossopharyngeal nerves of chimerae cause species-specific responsiveness during young adult, but that they tend to produce the responsiveness of X. laevis with aging.