Bao L, Kopp J, Zhang X, Xu Z Q, Zhang L F, Wong H, Walsh J, Hökfelt T
Department of Neuroscience, Karolinska Institute, S-171 77, Stockholm, Sweden.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12661-6. doi: 10.1073/pnas.94.23.12661.
The localization of neuropeptide Y (NPY) Y1 receptor (R) -like immunoreactivity (LI) has been studied in cerebral arteries and arterioles of the rat by immunohistochemistry using fluorescence, confocal, and electron microscopy. High levels of Y1-R-LI were observed in smooth muscle cells (SMCs) in the small arterioles of the pial arterial network, especially on the basal surface of the brain, and low levels in the major basal cerebral arteries. The levels of Y1-R-LI varied strongly between adjacent SMCs. Y1-R-LI was associated with small endocytosis vesicles, mainly on the outer surface of the SMCs, but also on their endothelial side and often laterally at the interface between two SMCs. NPY-immunoreactive (Ir) nerve fibers could not be detected in association with the Y1-R-rich small arterioles but only around arteries with low Y1-R levels. A dense network of central NPY-Ir nerve fibers in the superficial layers of the brain was lying close to the strongly Y1-R-Ir small arterioles. The results indicate that NPY has a profound effect on small arterioles of the brain acting on Y1-Rs, both on the peripheral and luminal side of the SMCs. However, the source of the endogenous ligand, NPY, remains unclear. NPY released from central neurons may play a role, in addition to blood-borne NPY.
通过荧光、共聚焦和电子显微镜免疫组织化学方法，对大鼠脑动脉和小动脉中神经肽Y（NPY）Y1受体（R）样免疫反应性（LI）的定位进行了研究。在软脑膜动脉网络的小动脉平滑肌细胞（SMC）中观察到高水平的Y1-R-LI，特别是在脑基底面，而在主要的脑基底动脉中水平较低。相邻SMC之间Y1-R-LI水平差异很大。Y1-R-LI与小的内吞小泡相关，主要在SMC的外表面，但也在其内皮侧，并且经常在两个SMC之间的界面处横向分布。在富含Y1-R的小动脉中未检测到与NPY免疫反应性（Ir）神经纤维相关联的情况，而仅在Y1-R水平低的动脉周围检测到。脑表层密集的中枢NPY-Ir神经纤维网络紧邻Y1-R-Ir强烈的小动脉。结果表明，NPY对作用于Y1-Rs的脑小动脉有深远影响，无论是在SMC的外周侧还是管腔侧。然而，内源性配体NPY的来源仍不清楚。除了血源性NPY外，中枢神经元释放的NPY可能也起作用。
