Hansen M A, Balcar V J, Barden J A, Bennett M R
The Institute for Biomedical Research and Department of Anatomy and Histology, The University of Sydney, NSW, Australia.
J Neurocytol. 1998;27(7):529-39. doi: 10.1023/a:1006908010642.
The distribution of purinergic (P2x1) receptors on smooth muscle cells in relation to autonomic nerve varicosities in the rat urinary bladder has been determined using immunofluorescence and confocal microscopy. P2x1 receptors were visualized using rabbit polyclonal antibodies against the extracellular domain of the P2x1 receptor, and varicosities were visualized using a mouse monoclonal antibody against the ubiquitous synaptic vesicle proteoglycan SV2. Two size classes of P2x1 receptor clusters were observed on the smooth muscle cells of the detrusor, namely, a large ellipse of mean long axis 1.23+/-0.21 microm and short axis 0.92+/-0.17 microm and a smaller spherical cluster with a mean diameter of 0.40+/-0.04 microm. The latter occured in much greater numbers than the former in selected areas, with a density as high as 0.8 per microm2 or two orders of magnitude more than the larger-sized clusters. The large clusters are in general located beneath varicosities, with only 4.5% of P2x1 clusters not possessing an overlying varicosity. None of the small clusters was associated with varicosities. Three-dimensional reconstruction of the P2x1 and SV2 labelling at individual varicosities showed that the varicosities were immediately apposed to the P2x1 receptor clusters. On occasions, two or more small SV2-labelled varicosities about 0.7 microm in diameter each with a receptor patch were found juxtaposed to each other; these might represent the splitting up of a single large varicosity. These observations are discussed in relation to the identity of the autonomic neuromuscular junction.
利用免疫荧光和共聚焦显微镜技术，已确定大鼠膀胱平滑肌细胞上嘌呤能（P2x1）受体的分布与自主神经膨体的关系。使用针对P2x1受体胞外域的兔多克隆抗体使P2x1受体可视化，使用针对普遍存在的突触囊泡蛋白聚糖SV2的小鼠单克隆抗体使膨体可视化。在逼尿肌的平滑肌细胞上观察到两类大小不同的P2x1受体簇，即平均长轴为1.23±0.21微米、短轴为0.92±0.17微米的大椭圆形簇和平均直径为0.40±0.04微米的较小球形簇。在选定区域，后者出现的数量比前者多得多，密度高达每平方微米0.8个，比大尺寸簇多两个数量级。大簇通常位于膨体下方，只有4.5%的P2x1簇上方没有膨体。小簇均与膨体无关。对单个膨体处P2x1和SV2标记进行三维重建显示，膨体紧邻P2x1受体簇。有时，会发现两个或更多直径约0.7微米、每个都带有受体斑块的小SV2标记膨体相互并列；这些可能代表单个大膨体的分裂。结合自主神经肌肉接头的特征对这些观察结果进行了讨论。
