Light- and electron-microscopic study of the distribution of axons containing substance P and the localization of neurokinin-1 receptor in bone
Light- and electron-microscopic study of the distribution of axons containing substance P and the localization of neurokinin-1 receptor in bone
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DOI：
10.1007/s004410051100
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发表时间：
1998-07-01
影响因子：
3.6
通讯作者：
Tanaka, T
中科院分区：
文献类型：
--
作者：
Goto, T;Yamaza, T;Tanaka, T
P物质（SP）是一种神经肽，其从感觉神经元的轴突释放并通过激活神经激肽- I受体（NK 1-R）引起信号转导。本研究采用抗生物素蛋白-生物素-过氧化物酶复合物法，观察了大鼠骨组织中SP样免疫反应阳性（SP-LI）轴突的分布和NK 1受体的定位。在颞骨骨髓中，SP-LI的轴突多见于骨小梁附近，而在下颌骨、股骨和胫骨中仅稀疏分布。在破骨细胞的质膜和细胞质中发现NK 1-Rs的免疫反应性。在成骨细胞和骨细胞中，少量弱的、点状的NK 1-Rs免疫反应产物分布在靠近质膜的位置。电镜下，NK 1-R免疫反应主要分布于整个胞浆。除了破骨细胞的透明区和沿着质膜的坑状结构。细胞质中的NK 1-R免疫反应结构分为两种类型的细胞器，包括囊泡和空泡结构（可能是运输囊泡和早期内体）。在成骨细胞和骨细胞中，NK 1-R阳性的泡状结构的数量少于破骨细胞。这些结果表明，感觉轴突分泌的SP可以通过NK 1-Rs直接调节骨代谢。
Substance P (SP) is a neuropeptide that is released from axons of sensory neurons and causes signal transduction through the activation of the neurokinin- I receptor (NK1-R). The present study demonstrates the distribution of SP-like-immunoreactive (SP-LI) axons and the localization of NK1-Rs in rat bone tissue using the avidin-biotin-peroxidase complex method. Axons with SP-LI were commonly found near the trabecular bone in the temporal bone marrow, but they were only sparsely distributed in the mandible, femur, and tibia. Immunoreactivity for NK1-Rs was found on the plasma membrane and in the cytoplasm of the osteoclasts. In the osteoblasts and osteocytes, a small number of weak, punctate immunoreactive products of NK1-Rs were distributed close to the plasma membrane. At the electron-microscopic level, immunoreactivity for NK1-R was distributed mainly in the whole cytoplasm. except for the clear zone of the osteoclasts, and in pit-like structures along the plasma membrane. The NK1-R-immunoreactive structures in the cytoplasm were divided into two types of organelles, consisting of vesicular and vacuolar structures (probably transport vesicles and early endosomes). In the osteoblasts and osteocytes, the number of NK1-R-positive vesicular structures was fewer than in the osteoclasts. These results thus suggest that SP secreted by the sensory axons could directly modulate bone metabolism via NK1-Rs.