Wakisaka S, Daikoku H, Miyawaki Y, Youn S H, Maeda T, Kurisu K
Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan.
Cell Tissue Res. 1998 Sep;293(3):499-507. doi: 10.1007/s004410051142.
The distribution and development of growth-associated protein 43 (GAP-43)-like immunoreactivity (-LI) in the rat circumvallate papilla (CVP) were compared to those of protein gene product 9.5 (PGP 9.5)-LI. In the adult, thick GAP-43-like immunoreactive (-IR) structures gathered densely in the subgemmal region. Some of these further penetrated the apical epithelium and trench wall epithelium. At least two types of GAP-43-IR structures were recognized; taste bud-related and non-gustatory GAP-43-IR neural elements. Immunoelectron microscopy revealed that GAP-43-LI was localized predominantly in the Schwann cells, and a few axons displayed GAP-43-LI in the lamina propria. In the trench epithelium, GAP-43-LI was detected in the cytoplasmic side of the axonal membrane. Some intragemmal GAP-43-IR axons made synaptic-like contacts with taste bud cells. At least four developmental stages were defined on the basis of the changes in distribution of GAP-43-LI. In stage I [embryonic day (E) 16-17] GAP-43-IR structures accumulated at the lamina propria just beneath the newly-formed circumvallate papilla. In stage II (E18-19) GAP-43-IR nerve fibers began to penetrate the apical epithelium. In stage III [E20-postnatal day (P) 0] GAP-43-IR nerve fibers first appeared in the trench wall epithelium. Penetration of GAP-IR nerve fibers occurred in the inner trench wall epithelium first, and then in the outer trench wall epithelium. In stage IV (P1-) the distribution of GAP-43-LI was similar to that observed in the adult; but the density of GAP-43-LI was much higher than in adults. PGP 9.5-LI showed a similar distribution pattern to that of GAP-43-LI, except for round-shaped cells in the apical epithelium at the late embryonic stages, and in taste bud cells and intralingual ganglionic cells which lacked GAP-43-LI. The similarities in distribution patterns of GAP-43-LI and PGP 9.5-LI during the development and mature circumvallate papilla suggest that GAP-43 may be a key neuronal molecule for induction and maintenance of the taste buds.
将大鼠轮廓乳头（CVP）中生长相关蛋白43（GAP - 43）样免疫反应性（-LI）的分布和发育与蛋白基因产物9.5（PGP 9.5）-LI的分布和发育进行了比较。在成年大鼠中，粗大的GAP - 43样免疫反应性（-IR）结构密集聚集在味蕾下区域。其中一些结构进一步穿透顶端上皮和沟壁上皮。至少识别出两种类型的GAP - 43免疫反应性结构；与味蕾相关的和非味觉性的GAP - 43免疫反应性神经成分。免疫电子显微镜显示，GAP - 43 - LI主要定位于施万细胞，少数轴突在固有层中显示GAP - 43 - LI。在沟上皮中，在轴突膜的胞质侧检测到GAP - 43 - LI。一些味蕾内GAP - 43免疫反应性轴突与味蕾细胞形成类似突触的接触。根据GAP - 43 - LI分布的变化至少确定了四个发育阶段。在I期[胚胎日（E）16 - 17]，GAP - 43免疫反应性结构聚集在新形成的轮廓乳头下方的固有层。在II期（E18 - 19），GAP - 43免疫反应性神经纤维开始穿透顶端上皮。在III期[E20 - 出生后日（P）0]，GAP - 43免疫反应性神经纤维首次出现在沟壁上皮。GAP免疫反应性神经纤维首先在内侧沟壁上皮穿透，然后在外沟壁上皮穿透。在IV期（P1 - ），GAP - 43 - LI的分布与成年大鼠中观察到的相似；但GAP - 43 - LI的密度比成年大鼠高得多。PGP 9.5 - LI显示出与GAP - 43 - LI相似的分布模式，除了在胚胎后期顶端上皮中的圆形细胞，以及在缺乏GAP - 43 - LI的味蕾细胞和舌内神经节细胞中。GAP - 43 - LI和PGP 9.5 - LI在发育和成熟的轮廓乳头中的分布模式相似，这表明GAP - 43可能是诱导和维持味蕾的关键神经元分子。
