Hansen M A, Dutton J L, Balcar V J, Barden J A, Bennett M R
The Institute for Biomedical Research, University of Sydney, NSW, Australia.
J Auton Nerv Syst. 1999 Feb 15;75(2-3):147-55. doi: 10.1016/s0165-1838(98)00189-1.
The distribution of purinergic (P2X1 and P2X2) receptors on smooth muscle cells in relation to autonomic nerve varicosities in rat blood vessels has been determined using immunofluorescence and confocal microscopy. P2X1 and P2X2 receptors were visualised using rabbit polyclonal antibodies against the extracellular domain of the receptors and varicosities visualised 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 mesenteric, renal, and pulmonary arteries as well as in the aorta and in veins: a large approximately elliptical cluster 1.32+/-0.21 microm long and 0.96+/-0.10 microm in diameter; and a smaller spherical cluster with a diameter of 0.32+/-0.05 microm. The latter occurred throughout the media of arteries of all sizes, whereas the former were restricted to the adventitial surface of the media and to endothelial cells, except for the pulmonary artery, in which large receptor clusters were found throughout the media of the vessel. At the adventitial surface, the large clusters are in general located beneath SV2 labelled varicosities. None of the small clusters was associated with varicosities. Three-dimensional reconstruction of the P2X and SV2 labelling at individual varicosities showed that the varicosities were immediately apposed to the P2X receptor clusters. P2X2 receptors were located on nerves and on endothelial cells. They were also found in low density on the smooth muscle cells in the media. These observations are discussed in relation to the mechanism of purinergic transmission to the smooth muscle cells of blood vessels.
利用免疫荧光和共聚焦显微镜技术，已确定大鼠血管中平滑肌细胞上嘌呤能（P2X1和P2X2）受体的分布与自主神经膨体的关系。使用针对受体细胞外结构域的兔多克隆抗体对P2X1和P2X2受体进行可视化，使用针对普遍存在的突触小泡蛋白聚糖SV2的小鼠单克隆抗体对膨体进行可视化。在肠系膜动脉、肾动脉、肺动脉以及主动脉和静脉的平滑肌细胞上观察到两类大小不同的P2X1受体簇：一类大的近似椭圆形簇，长1.32±0.21微米，直径0.96±0.10微米；另一类较小的球形簇，直径为0.32±0.05微米。后者出现在所有大小动脉的中膜各处，而前者仅限于中膜的外膜表面和内皮细胞，但肺动脉除外，在肺动脉中整个血管中膜都发现有大的受体簇。在外膜表面，大的受体簇通常位于SV2标记的膨体下方。小的受体簇均与膨体无关。对单个膨体处P2X和SV2标记进行三维重建显示，膨体紧邻P2X受体簇。P2X2受体位于神经和内皮细胞上。在中膜的平滑肌细胞上也发现其低密度分布。结合嘌呤能传递至血管平滑肌细胞的机制对这些观察结果进行了讨论。
