A VERTEBRATE-LIKE BLOOD-BRAIN-BARRIER, WITH INTRAGANGLIONIC BLOOD CHANNELS AND OCCLUDING JUNCTIONS, IN THE SCORPION
A VERTEBRATE-LIKE BLOOD-BRAIN-BARRIER, WITH INTRAGANGLIONIC BLOOD CHANNELS AND OCCLUDING JUNCTIONS, IN THE SCORPION
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DOI：
10.1016/0040-8166(81)90027-6
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发表时间：
1981-01-01
期刊：
影响因子：
2.6
通讯作者：
BOWERMAN, RF
中科院分区：
文献类型：
--
作者：
LANE, NJ;HARRISON, JB;BOWERMAN, RF
印度墨水和离子La注射显示，蝎子的中枢神经系统具有高度血管化的头胸神经节肿块。它和其他腹部神经节一起构成腹侧神经索，都被一层修饰的胶质细胞或神经周围细胞包裹着。这些细胞类似于渗透中枢神经系统的血液通道，表现出倒置的间隙和紧密的连接。虽然后者表现出紧密或融合的膜偶联，但La似乎穿透了一些膜偶联，但不是全部。冷冻破裂显示，这些连接是由排列成行或脊状网络的e面粒子组成的，它们经常是不连续的，特别是在神经会膜的周围。这产生了一个有点渗漏的系统，但最终会发生对示踪剂的阻塞，因为在中枢神经系统中，除了神经膜外没有发现示踪剂。这种神经周围血脑屏障的存在也在电生理学上得到证实，其中阳离子（如Mg2+）虽然似乎可以通过血管系统渗入，但却无法穿透神经周围层。神经会膜和血管细胞之间紧密度的相对差异可能归因于不连续脊的相对数量的差异。观察到周围神经系统有高度衰减的神经周围膜，连接较少，其中一些神经由于示踪剂的渗透而趋于渗漏，这证实了这一点。在固定材料中，连接脊可能在e面或部分在EF和PF上断裂，在非固定组织中，它们通常在PF上发现。在这两种情况下，它们都表现出与跨膜过渡的脊一致的互补凹槽；在这种情况下，细胞膜融合，同时细胞间隙闭塞。这些紧密连接通常与EF间隙连接颗粒聚集体密切相关，可能非常松散地聚集在一起，似乎形成了观察到的蝎子中枢神经系统血脑屏障的基础。
India ink and ionic La injections have revealed that the CNS of the scorpion possesses a highly vascularized cephalothoracic ganglionic mass. It, together with other abdominal ganglia which form a ventral nerve cord, are all ensheathed by an outer layer of modified glial, or perineurial, cells. These cells resemble those which line the blood channels permeating the CNS, in exhibiting inverted gap and tight junctions. Although the latter show close or fused membrane appositions La appears to penetrate past a number, but not all, of them. Freeze-fracturing reveals that these junctions are composed of E-face particles aligned into a network of rows, or ridges, which are frequently discontinuous, especially near the periphery of the perineurium. This produces a somewhat leaky system but occlusion to tracers occurs ultimately, for in the CNS none can be found beyond the perineurium. The existence of this perineurial blood-brain barrier is also demonstrable electrophysiologically where cations such as Mg2+ are unable to penetrate beyond the perineurial layer although they can, it seems, leak in via the blood vascular system. Relative differences in tightness between the perineurium and the cells lining the blood channels may be attributed to differences in the relative number of discontinuous ridges. This is borne out by the observation that the peripheral nervous system has a highly attenuated perineurium with many fewer junctions, and some of these nerves tend to be leaky with respect to tracer penetration. In fixed material the junctional ridges may fracture on the E-face or partly on the EF and PF, in unfixed tissue they are usually found on the PF. In both cases they exhibit complementary grooves that are coincident with the ridges across membrane transitions; in such cases the cell membranes are fused with concomitant obliteration of the intercellular space. These tight junctions, often closely associated with EF gap junctional particle aggregates which may be very loosely clustered, appear to form the basis of the observed blood-brain barrier in the scorpion CNS.