Miyawaki Y, Morisaki I, Tabata M J, Maeda T, Kurisu K, Wakisaka S
Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565, Japan.
Cell Tissue Res. 1998 Jan;291(1):81-90. doi: 10.1007/s004410050981.
The distribution of calbindin D28k (CB)-like immunoreactivity (-LI) in the circumvallate papilla (CVP) was examined during development and regeneration following bilateral crush injury to the glossopharyngeal nerve in the rat. In the adult CVP, CB-like immunoreactive (-IR) nerve fibers were observed in the subgemmal region and some penetrated into the taste buds. CB-LI was also detected in the cytoplasm of the spindle-shaped gustatory cells in the lower half of the trench epithelium, which contained numerous synaptic vesicles and bundles of intermediate filaments. These CB-IR gustatory cells made synapse-like contacts with CB-IR nerve terminals. Some CB-IR nerve terminals made contacts with the gustatory cells negative for CB-LI. At least three developmental stages were defined with regard to the developmental changes in the distribution of CB-LI: (1) Stage I (embryonic day (E) 18-postnatal day (P)5): CB-IR nerve fibers appeared in the lamina propria just beneath the newly-formed CVP at E18, but the gustatory epithelium of the CVP contained no CB-IR structures. Taste buds with taste pores appeared at P1. (2) Stage II (P5-10): thin CB-IR nerve fibers began entering the trench epithelium, but no CB-IR cells were observed. (3) Stage III (P10-adult): in addition to the intragemmal and perigemmal CB-IR nerve fibers, very few CB-IR cells appeared in the taste buds around P10, and their numbers increased progressively. The changes in the distribution of taste buds and CB-LI following glossopharyngeal nerve injury were similar to those observed during development. On post-operative day (PO) 4, the taste buds and CB-IR cells decreased markedly in number. These CB-IR cells became round in shape, and the number of CB-IR nerve fibers decreased markedly. On PO8, both taste buds and CB-IR cells disappeared completely. The regenerated taste buds were first observed on PO12, increased rapidly in number by PO20, and increased slowly thereafter. CB-IR nerve fibers accumulated at the subgemmal region and began penetrating into the trench wall epithelium around PO16. CB-IR cells appeared between PO20 and PO24, and their numbers increased progressively and reached the normal level on PO40. The topographical localizations of the taste buds and CB-IR cells during development and regeneration were comparable to those of normal animals. The delay of the time courses for appearance of CB-IR nerve fibers and CB-IR cells compared to the appearance of taste buds during development and regeneration suggests that CB in the gustatory epithelium may participate in the survival of the taste bud cells rather than in the induction of the taste buds.
在大鼠双侧舌咽神经挤压伤后的发育和再生过程中，研究了轮廓乳头（CVP）中钙结合蛋白D28k（CB）样免疫反应性（-LI）的分布。在成年CVP中，在味蕾下区域观察到CB样免疫反应性（-IR）神经纤维，一些神经纤维穿透到味蕾中。在沟状上皮下半部的梭形味觉细胞的细胞质中也检测到CB-LI，这些细胞含有大量突触小泡和成束的中间丝。这些CB-IR味觉细胞与CB-IR神经末梢形成突触样接触。一些CB-IR神经末梢与CB-LI阴性的味觉细胞接触。关于CB-LI分布的发育变化，至少定义了三个发育阶段：（1）第一阶段（胚胎第（E）18天-出生后第（P）5天）：E18时，CB-IR神经纤维出现在新形成的CVP下方的固有层中，但CVP的味觉上皮中没有CB-IR结构。P1时出现有 taste pores的味蕾。（2）第二阶段（P5-10）：细的CB-IR神经纤维开始进入沟状上皮，但未观察到CB-IR细胞。（3）第三阶段（P10-成年）：除了味蕾内和味蕾周围的CB-IR神经纤维外，P10左右味蕾中出现极少数CB-IR细胞，其数量逐渐增加。舌咽神经损伤后味蕾和CB-LI分布的变化与发育过程中观察到的相似。术后第（PO）4天，味蕾和CB-IR细胞数量明显减少。这些CB-IR细胞变为圆形，CB-IR神经纤维数量明显减少。PO8时，味蕾和CB-IR细胞完全消失。再生的味蕾最早在PO12时观察到，PO20时数量迅速增加，此后缓慢增加。CB-IR神经纤维在味蕾下区域聚集，并在PO16左右开始穿透到沟壁上皮中。CB-IR细胞在PO20至PO24之间出现，其数量逐渐增加，并在PO40时达到正常水平。发育和再生过程中味蕾和CB-IR细胞的地形定位与正常动物的相似。与发育和再生过程中味蕾出现相比，CB-IR神经纤维和CB-IR细胞出现的时间进程延迟表明，味觉上皮中的CB可能参与味蕾细胞的存活，而不是味蕾的诱导。
