Carmanchahi P D, Aldana Marcos H J, Ferrari C C, Affanni J M
Institute of Neurosciences, University of Buenos Aires, Argentina.
J Anat. 1999 Nov;195 ( Pt 4)(Pt 4):587-604. doi: 10.1046/j.1469-7580.1999.19540587.x.
The vomeronasal organ (VNO) is a chemoreceptive structure that has not been extensively studied in the Xenarthran order. Tissue samples from the VNO of the armadillo Chaetophractus villosus were prepared for light and electron microscopy. The VNO is located in the anterior part of the base of the nasal septum. It is tubular in shape, approximately 18 mm in length and opens in the rostral region of the nasal cavity and with a blind caudal end. Its lumen is lined by sensory (SE) and nonsensory (NSE) epithelium. The SE shows sensory, supporting and basal cells whereas the NSE contains ciliated and nonciliated secretory cells and basal cells. At the ultrastructural level, the sensory cells appear as bipolar neurons with conspicuous microvilli on their free surface. The supporting cells of the SE contain numerous membrane-bound vesicles in their apical regions. A peculiar feature not found in other mammals, is the presence of concentric whorls of RER cisterns frequently observed in their basal expansions. Infiltrating plasma cells can be detected in the SE basal region close to the dorsal junctional area. This region also exhibits an unusual type of basal cell, probably responsible for the generation of new vomeronasal receptor neurons. The ciliated NSE cells exhibit numerous ovoids or irregularly shaped membranous protrusions projecting from the plasma membrane of the cilia. As far as we know, this is the first study reporting the presence of this feature in ciliated NSE cells. The nonciliated cells are characterised by scarce large secretory granules and apical microvilli. The vomeronasal glands are compound-branched tubuloacinar glands with serous acinar cells. Four types of secretory granules are present. The ducts of these glands reach the lumen in the dorsolateral region between the NSE and SE. Hypolemmal nerve terminals were observed contacting secretory cells. Fenestrated and nonfenestrated capillaries constitute the vascular supply to these glands. Plasma cells, intimately associated with acinar cells, were frequently observed.
犁鼻器（VNO）是一种化学感受结构，在贫齿目动物中尚未得到广泛研究。制备了犰狳Chaetophractus villosus犁鼻器的组织样本用于光学显微镜和电子显微镜观察。犁鼻器位于鼻中隔基部的前部。它呈管状，长度约为18毫米，开口于鼻腔的吻侧区域，尾端为盲端。其管腔由感觉上皮（SE）和非感觉上皮（NSE）衬里。感觉上皮显示出感觉细胞、支持细胞和基底细胞，而非感觉上皮包含纤毛和非纤毛分泌细胞以及基底细胞。在超微结构水平上，感觉细胞表现为双极神经元，其游离表面有明显的微绒毛。感觉上皮的支持细胞在其顶端区域含有大量膜结合小泡。在其基部扩张处经常观察到粗面内质网池的同心环，这是其他哺乳动物中未发现的一个独特特征。在靠近背侧连接区域的感觉上皮基部区域可检测到浸润的浆细胞。该区域还呈现出一种不寻常类型的基底细胞，可能负责新犁鼻器受体神经元的产生。纤毛非感觉上皮细胞在纤毛的质膜上有许多卵形或不规则形状的膜性突起。据我们所知，这是第一项报道纤毛非感觉上皮细胞中存在此特征的研究。非纤毛细胞的特征是稀少的大分泌颗粒和顶端微绒毛。犁鼻腺是具有浆液性腺泡细胞的复分支管状腺泡腺。存在四种类型的分泌颗粒。这些腺体的导管在非感觉上皮和感觉上皮之间的背外侧区域通向管腔。观察到皮下神经末梢与分泌细胞接触。有孔和无孔毛细血管构成了这些腺体的血管供应。经常观察到与腺泡细胞紧密相关的浆细胞。
