LIGHT AND ELECTRON-MICROSCOPIC IMMUNOCYTOCHEMICAL ANALYSIS OF THE NEUROVASCULAR RELATIONSHIPS OF CHOLINE-ACETYLTRANSFERASE AND VASOACTIVE INTESTINAL POLYPEPTIDE NERVE-TERMINALS IN THE RAT CEREBRAL CARTER
LIGHT AND ELECTRON-MICROSCOPIC IMMUNOCYTOCHEMICAL ANALYSIS OF THE NEUROVASCULAR RELATIONSHIPS OF CHOLINE-ACETYLTRANSFERASE AND VASOACTIVE INTESTINAL POLYPEPTIDE NERVE-TERMINALS IN THE RAT CEREBRAL CARTER
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DOI：
10.1002/cne.903430105
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发表时间：
1994-05-01
影响因子：
2.5
通讯作者：
HAMEL, E
中科院分区：
文献类型：
--
作者：
CHEDOTAL, A;UMBRIACO, D;HAMEL, E
与皮质内血管密切相关的乙酰胆碱或血管活性肠肽（VIP）神经末梢先前已有报道。最近的生理学证据表明，这些中枢神经系统参与了局部脑血流的精细控制。在本研究中，胆碱乙酰转移酶（ChAT）和VIP轴突终末和皮质内微血管之间的密切联系的特点是光（LM）和电子显微镜（EM）免疫细胞化学。在半薄切片中，ChAT和VIP免疫染色斑点与小的脑实质内血管并列的分布的LM分析表明，无论是哪种类型的终端在大脑皮层内的微血管周围富集或贫困。在EM水平上，大多数ChAT或VIP免疫标记的元素位于血管壁周围3 μ m的周长轴突终端。这些血管周围末梢主要与毛细血管相关，但也在较小程度上与微动脉相关。即使ChAT和VIP终端经常被发现在紧邻（小于或等于0.25 μ m）的微血管，他们几乎从来没有接触外基板，通常邻接血管周围的星形胶质细胞小叶。ChAT或VIP终末与血管周围星形胶质细胞之间的接触部位没有膜特化。在所有检查的皮质区域中，VIP免疫标记的静脉曲张的平均大小（0.56 ± 0.04 μ m（2））明显大于ChAT对应物（0.32 ± 0.02 μ m（2）; P < 0.001）。血管周围VIP终端更频繁地从事突触接触比那些免疫染色的ChAT，很少表现出突触连接，即使在连续薄切片。VIP和ChAT均未在内皮细胞中表达，提示乙酰胆碱和VIP均通过间接的旁分泌机制对皮质内微血管产生影响。两种类型的血管周围末梢之间的突触发生率和平均大小的显着差异表明，这两种血管活性剂主要位于不同的神经元群体。此外，我们的研究结果表明，星形胶质细胞是主要的直接目标，为ChAT和VIP血管周围终端，并建议，神经元/胶质细胞/血管的相互作用是一个关键因素，在神经源性控制的皮质内微循环。(C)1994 Wiley-Liss，Inc.
Acetylcholine or vasoactive intestinal peptide (VIP) nerve terminals closely related to intracortical blood vessels have previously been reported. Recent physiological evidence indicates that these central neuronal systems are involved in the fine control of local cerebral blood flow. In the present study, the intimate associations between choline acetyltransferase (ChAT) and VIP axon terminals and intracortical microvessels were characterized by light (LM) and electron microscopic (EM) immunocytochemistry. In semithin sections, LM analysis of the distribution of ChAT- and VIP-immunostained puncta juxtaposed to small intraparenchymal blood vessels demonstrated that neither type of terminal was enriched or impoverished around microvessels within the cerebral cortex. At the EM level, most ChAT- or VIP-immunolabelled elements located within a 3 mu m perimeter around vessel walls were axon terminals. These perivascular terminals were associated primarily with capillaries but also, to a lesser extent, with microarterioles. Even though ChAT and VIP terminals were frequently found in the immediate vicinity (less than or equal to 0.25 mu m) of microvessels, they almost never contacted the outer basal lamina, usually abutting onto perivascular astroglial leaflets. There were no membrane specializations at the site of contact between ChAT or VIP terminals and perivascular astroglia. In all cortical areas examined, the average size of VIP-immunolabelled varicosities (0.56 +/- 0.04 mu m(2)) was significantly larger than that of their ChAT counterparts (0.32 +/- 0.02 mu m(2); P < 0.001). Perivascular VIP terminals were more frequently engaged in synaptic contact than those immunostained for ChAT, which rarely exhibited a synaptic junction even in serial thin sections. Neither VIP nor ChAT immunostaining was ever observed in endothelial cells.These results suggest that both acetylcholine and VIP exert their effects on intracortical microvessels through indirect, paracrine mechanisms. The marked difference in synaptic incidence and average size between both types of perivascular terminals indicates that these two vasoactive agents are primarily located in distinct neuronal populations. Further, our results show that the astrocytic glia is the major direct target for both ChAT and VIP perivascular terminals and suggest that neuronal/glial/vascular interactions are a key element in the neurogenic control of the intracortical microcirculation. (C) 1994 Wiley-Liss, Inc.