Distribution and density of alpha-bungarotoxin binding sites on innervated and noninnervated Xenopus muscle cells in culture.
Distribution and density of alpha-bungarotoxin binding sites on innervated and noninnervated Xenopus muscle cells in culture.
复制标题
培养物中神经支配和非神经支配的非洲爪蟾肌肉细胞上α-银环蛇毒素结合位点的分布和密度。
DOI：
10.1016/0012-1606(82)90010-0
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发表时间：
1982
影响因子：
2.7
通讯作者：
Gruener,R
中科院分区：
文献类型：
--
作者：
Kidokoro,Y;Gruener,R
本文用~（125）I-α-银环蛇毒素（α-BT）放射自显影技术，研究了α-BT结合位点在体外培养的爪蟾肌细胞上的分布和密度。在单独生长的肌细胞中，α-BT结合位点相当均匀地分布在整个表面上，平均密度为104/μm2（背景密度）。偶尔也会观察到较高密度的斑点（“热点”），平均密度为890/μm2。神经管细胞的加入没有改变背景密度。同样，在大多数情况下，含有神经管细胞的培养基不影响α-BT结合位点的密度。以前的研究结果，即背景乙酰胆碱敏感性的肌细胞增加神经管细胞（约50%）或条件培养基（约70%）的存在下，因此，不太可能主要是由于乙酰胆碱受体（AChR）密度的增加。在神经和肌肉细胞的共培养中，高α-BT结合位点的区域偶尔与神经突起的路径相关。在这些区域中，α-BT结合位点的密度估计约为1000个/μm2。然而，即使在这些细胞中，在非神经接触区域的密度与单独培养的肌细胞中的密度没有不同。AChR密度在交界区的增加是否足以解释以前的观察AChR积累的过程中自发突触电位的振幅增加了五倍进行了讨论。
The distribution and density of α-bungarotoxin (α-BT) binding sites onXenopusmuscle cells in culture by autoradiography using125I-α-BT were examined. In muscle cells grown alone α-BT binding sites were fairly uniformly distributed over the entire surface with a mean density of 104/μm2(background density). Occasionally, spots of higher density were observed (“hot spots”) where the mean density was 890/μm2. The addition of neural tube cells did not change the background density. Similarly in the majority of cases medium contained with neural tube cells did not affect the density of α-BT binding sites. Previous findings that the background acetylcholine sensitivity of muscle cells increased in the presence of neural tube cells (by approximately 50%) or in conditioned medium (by approximately 70%), therefore, are not likely due primarily to an increase in the acetylcholine receptor (AChR) density. In cocultures of nerve and muscle cells regions of high α-BT binding sites were occasionally associated with the path of neurites. In such regions the density of α-BT binding sites was estimated to be approximately 1000/μm2. However, even in these cells the density at non-nerve contacted regions was not different from that in muscle cells cultured alone. Whether the increase in AChR density at the junctional area is sufficient to explain a previous observation of a fivefold increase in the amplitude of spontaneous synaptic potentials during the process of AChR accumulation is discussed.