Merlie J P, Heinemann S, Lindstrom J M
J Biol Chem. 1979 Jul 25;254(14):6320-7.
Acetylcholine receptor located at the neuromuscular synapse of normal innervated adult muscle fibers is extremely stable metabolically. We have studied the kinetics of receptor degradation in both normal innervated and denervated rat diaphragms in organ culture. These studies show that degradation of receptor-bound 125I-alpha-bungarotoxin is a valid measure of junctional receptor degradation. Degradation of junctional receptor is similar or identical to degradation of extrajunctional receptor in many ways: 1) both require energy, 2) both are inhibited by specific lysosomal protease inhibitors, 3) both are inhibited by treatment with colchicine, and 4) both are stimulated by treatment with anti-acetylcholine receptor antibodies. The one important distinction between degradation of junctional and extrajunctional receptor is a 10-fold difference in rate constant for the process.
位于正常神经支配的成年肌纤维神经肌肉突触处的乙酰胆碱受体在代谢上极其稳定。我们在器官培养中研究了正常神经支配和去神经支配的大鼠膈肌中受体降解的动力学。这些研究表明，受体结合的125I-α-银环蛇毒素的降解是连接受体降解的有效指标。连接受体的降解在许多方面与接头外受体的降解相似或相同：1）两者都需要能量，2）两者都受到特异性溶酶体蛋白酶抑制剂的抑制，3）两者都受到秋水仙碱处理的抑制，4）两者都受到抗乙酰胆碱受体抗体处理的刺激。连接受体和接头外受体降解之间的一个重要区别是该过程的速率常数相差10倍。
