DENERVATION INCREASES TURNOVER RATE OF JUNCTIONAL ACETYLCHOLINE-RECEPTORS
DENERVATION INCREASES TURNOVER RATE OF JUNCTIONAL ACETYLCHOLINE-RECEPTORS
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DOI：
10.1073/pnas.77.4.2293
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
SALPETER, MM
中科院分区：
文献类型：
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作者：
LORING, RH;SALPETER, MM
通过125 I-标记的α-乙酰胆碱受体在神经支配和去神经支配的小鼠胸锁乳突肌神经肌肉接头中测量接头乙酰胆碱受体的转换率。银环蛇毒素结合标记毒素的密度最初绑定到神经肌肉接头基本上没有变化，直到16天后去神经。然后用标记的毒素饱和受神经支配的肌肉和8天前已去神经支配的肌肉，并通过γ比较终板区域的特异性标记。7天后开始计算。当时，神经支配肌肉中观察到的残留交界标记是去神经肌肉中的3.2倍。电子显微镜放射自显影进一步表明，饱和后与未标记的毒素，新的结合位点迅速出现在专门的接受区的突触后膜与一个明显的半衰期为2-3天的营业额。在神经支配的交界处，营业额的半衰期为. apprx。10天控制受体周转率的机制与控制高密度受体聚集的机制不同。连接受体的缓慢周转率似乎比连接受体的聚集更直接地依赖于神经的存在。
The turnover rates of junctional acetylcholine receptors were measured in innervated and denervated mouse sternomastoid neuromuscular junctions by 125I-labeled .alpha.-bungarotoxin binding. The density of labeled toxin initially bound to the neuromuscular junction was essentially unchanged up to 16 day after denervation. Innervated muscles and muscles that had been denervated 8 days previously were then saturated with labeled toxin, and the specific label at the endplate regions was compared by .gamma. counting 7 days later. At that time, the residual junctional label seen in innervated muscle was 3.2 times greater than in denervated muscle. Electron microscope autoradiography further showed that, after saturation with unlabeled toxin, new binding sites appeared rapidly at the specialized receptive region of the postsynaptic membrane with an apparent half-time of turnover of 2-3 days. At innervated junctions, the half-time of turnover was .apprx. 10 days. The mechanisms that control receptor turnover rates are different from those that control high-density receptor clustering. The slow turnover rate of junctional receptors appears to be more directly dependent on the presence of the nerve than is the clustering of junctional receptors.