Abstract：
The flower-spray nerve endings are afferent nerve terminals in the carotid sinus that arise from carotid sinus nerve of glossopharyngeal nerve. However, the three-dimensional ultrastructural characteristics of flower-spray nerve endings and spatial relationships between the terminal parts and other cellular elements have not been fully understood. To elucidate their detailed relationship, backscattered electron imaging of serial sections was performed with a scanning electron microscope to produce a three-dimensional reconstruction of the flower-spray endings. The terminal parts of flower-spray endings were distributed horizontally approximately 5 µm outside the external elastic membrane in the tunica adventitia of the internal carotid artery. The three-dimensional reconstruction showed that the terminal parts of flower-spray endings were flat with irregular contours and were partially covered by the thin cytoplasmic processes of Schwann cells. The complex consisting of the nerve terminals and associated Schwann cells was surrounded by a multilayered basement membrane. The terminal parts of the endings were also surrounded by fibroblasts with elastic fibers and collagen fibrils. Secretory vesicles without an electron-dense core were observed in the terminal parts of the endings. The accumulation of vesicles just below the axonal membrane was observed in terminal parts not covered by Schwann cell cytoplasmic processes on both the luminal and basal sides. Swollen mitochondria, concentric membranous structures, and glycogen granule-like electron-dense materials were often noted in some of the terminal parts of the endings and the parent axon. Collectively, the present results suggest that flower-spray endings are baroreceptors because their morphology was similar to other mechanoreceptors. Furthermore, flower-spray endings may be affected by glutamate secreted in an autocrine manner.
摘要：
花喷神经末梢是由舌咽神经的颈动脉窦神经产生的颈动脉窦内的传入神经末梢。然而,尚未完全了解花喷雾神经末梢的三维超微结构特征以及末端部分与其他细胞元素之间的空间关系。为了阐明他们的详细关系，用扫描电子显微镜对连续切片进行背散射电子成像，以产生花喷雾末端的三维重建。喷花末端的末端部分水平分布在颈内动脉外膜的外弹性膜外约5µm处。三维重建显示，花喷雾末端的末端部分平坦，轮廓不规则，部分被雪旺氏细胞的细细胞质突起覆盖。由神经末梢和相关的雪旺氏细胞组成的复合物被多层基底膜包围。末端的末端部分也被具有弹性纤维和胶原纤维的成纤维细胞包围。在末端的末端观察到没有电子致密核的分泌性囊泡。在腔侧和基底侧都未被雪旺氏细胞细胞质过程覆盖的末端部分观察到轴突膜正下方的囊泡积累。线粒体肿胀,同心膜状结构，在末端和母体轴突的某些末端部分经常注意到糖原颗粒状电子致密材料。总的来说，目前的结果表明，喷花末端是压力感受器，因为它们的形态与其他机械感受器相似。此外，花喷雾的末端可能会受到自分泌方式分泌的谷氨酸的影响。
