Tuor U I, Kelly P A, Edvinsson L, McCulloch J
Biomedical Research Division, Hospital for Sick Children, Toronto, Ontario, Canada.
J Cereb Blood Flow Metab. 1990 Sep;10(5):591-601. doi: 10.1038/jcbfm.1990.110.
The significance of neuropeptide Y (NPY) in the cerebral circulation has been examined in the rat using immunocytochemistry, isolated cerebral artery preparations, and quantitative autoradiographic techniques for determining local CBF and glucose utilisation. In the rat the middle cerebral artery and the lenticulostriate artery from which blood is supplied to the caudate nucleus were found to be invested with numerous perivascular NPY immunoreactive nerve fibres. NPY (3-300 nM) contracted rat middle cerebral artery segments in a concentration-dependent manner. Intracerebral microinjections of NPY (200 pmol) or vehicle (1 microliter) were performed in rats after full recovery from anaesthesia via previously implanted guide cannulae. Following injection of NPY into the striatum, local blood flow was markedly decreased by 36% throughout the ipsilateral caudate nucleus (e.g., from 104 +/- 25 to 67 +/- 15 ml 100 g-1 min-1; mean +/- SD), whereas glucose use in this region was not altered significantly (e.g., 73 +/- 8 and 74 +/- 10 mumol 100 g-1 min-1 with vehicle and NPY, respectively). Intrastriatal NPY did not alter CBF or glucose use in the majority of other brain areas, including all of the 40 contralateral regions examined and almost all regions within the ipsilateral hemisphere. In a small number of highly discrete brain areas remote from the injection site (e.g., amygdala), there were significant reductions in blood flow with minimal changes in glucose use. Since NPY is present around rat cerebral blood vessels, is capable of evoking their contraction, and has the ability to produce reductions in blood flow independently of oxidative metabolism, this neuropeptide may be of major importance in cerebrovascular regulation.
利用免疫细胞化学、离体脑动脉制备以及用于测定局部脑血流量（CBF）和葡萄糖利用的定量放射自显影技术，在大鼠中研究了神经肽Y（NPY）在脑循环中的意义。在大鼠中，发现向尾状核供血的大脑中动脉和豆纹动脉有许多血管周围NPY免疫反应性神经纤维。NPY（3 - 300 nM）以浓度依赖的方式收缩大鼠大脑中动脉段。在大鼠从麻醉中完全恢复后，通过先前植入的引导套管进行脑内微量注射NPY（200 pmol）或溶媒（1微升）。将NPY注射到纹状体后，同侧整个尾状核的局部血流量显著降低36%（例如，从104±25降至67±15 ml 100 g-1 min-1；平均值±标准差），而该区域的葡萄糖利用没有明显改变（例如，分别用溶媒和NPY时为73±8和74±10 μmol 100 g-1 min-1）。纹状体内注射NPY并未改变大多数其他脑区的CBF或葡萄糖利用，包括所有检查的40个对侧区域以及同侧半球内几乎所有区域。在少数远离注射部位的高度离散脑区（如杏仁核），血流量显著减少，而葡萄糖利用变化最小。由于NPY存在于大鼠脑血管周围，能够引起血管收缩，并且能够独立于氧化代谢减少血流量，这种神经肽可能在脑血管调节中起重要作用。
