Taniguchi K, Toshima Y, Saito T R, Taniguchi K
Department of Anatomy II, Iwate Medical University School of Medicine, Japan.
J Vet Med Sci. 1996 Jan;58(1):7-15. doi: 10.1292/jvms.58.7.
Histological and ultrastructural development of the olfactory epithelium (OE) and vomeronasal organ (VNO) was investigated in the Japanese reddish frog, Rana japonica. Tadpoles, from hatching to the end of metamorphosis, and adult frogs were examined. In the adult, olfactory cells of the OE were equipped with olfactory vesicles with long cilia, but supporting cells with microvilli. The supporting cells of the OE contained secretory granules, PAS-positive by light microscopy, in their apical cytoplasm. On the contrary, sensory cells of the VNO were equipped with microvilli, and supporting cells of the VNO were equipped with cilia, but without secretory granules. Embryologically, the olfactory cells were indistinguishable from the supporting cells in the olfactory placode (primitive OE) lining the nasal pit, at hatch. The VNO appeared as a concave of the ventral part of the OE at 4 days after hatch. At the time, the olfactory and supporting cells of the OE became distinguishable from each other. Secretory granules were formed in the supporting cells of the OE at 36 days after hatch, and the OE was similar in fine structure to that in the adult. While, the VNO remained immature at 24-36 days after hatch, and did not complete its ultrastructural development at 60 days after hatch, the end of metamorphosis. These findings suggest that the OE may take part in the olfaction earlier than the VNO in ontogeny.
对日本赤蛙（Rana japonica）的嗅觉上皮（OE）和犁鼻器（VNO）的组织学和超微结构发育进行了研究。研究对象包括从孵化到变态结束的蝌蚪以及成年蛙。在成年蛙中，OE的嗅觉细胞配备有带有长纤毛的嗅泡，而支持细胞则带有微绒毛。OE的支持细胞在其顶端细胞质中含有分泌颗粒，通过光学显微镜观察呈PAS阳性。相反，VNO的感觉细胞配备有微绒毛，VNO的支持细胞配备有纤毛，但没有分泌颗粒。在胚胎学上，孵化时，嗅觉细胞与位于鼻凹内衬的嗅基板（原始OE）中的支持细胞无法区分。VNO在孵化后4天表现为OE腹侧部分的凹陷。此时，OE的嗅觉细胞和支持细胞开始彼此区分。孵化后36天，OE的支持细胞中形成了分泌颗粒，此时OE的精细结构与成年蛙相似。而VNO在孵化后24 - 36天仍未成熟，在孵化后60天（变态结束时）也未完成其超微结构发育。这些发现表明，在个体发育过程中，OE可能比VNO更早参与嗅觉。
