Rozental R
Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Ilha do Fundão, Brazil.
Neurosci Lett. 1991 Nov 25;133(1):65-7. doi: 10.1016/0304-3940(91)90058-2.
The question arose as to whether the altered kinetic properties of the nicotinic acetylcholine receptor-ion channel complex (AChR) observed after muscle denervation could be due to post-translational modifications. Single AChR properties of in vitro denervated skeletal muscle were studied using the cell-attached patch-clamp technique. Patch-clamp recordings from junctional regions of fibers daily treated with cycloheximide, a protein synthesis inhibitor, and phenylmethylsulfonyl fluoride, a protease inhibitor, revealed single conductance class of acetylcholine (ACh)-activated currents after acute dissociation and several conductance classes 3-14 days after muscle denervation. alpha-Bungarotoxin blocked all conductance states induced by ACh. Biochemical assays carried out on the same experimental conditions disclosed that chronic treatment of the fibers with cycloheximide inhibited the incorporation of [3H]leucine into precipitable protein. The present findings provided evidence that the altered functional properties of nicotinic receptors after muscle denervation may occur without new transcription.
肌肉去神经支配后观察到的烟碱型乙酰胆碱受体 - 离子通道复合物（AChR）动力学特性的改变是否可能归因于翻译后修饰，这一问题由此产生。使用细胞贴附式膜片钳技术研究了体外去神经支配骨骼肌的单个AChR特性。对每日用蛋白质合成抑制剂环己酰亚胺和蛋白酶抑制剂苯甲基磺酰氟处理的纤维的连接区域进行膜片钳记录，结果显示急性解离后乙酰胆碱（ACh）激活电流的单一电导类别，以及肌肉去神经支配后3 - 14天的几种电导类别。α - 银环蛇毒素阻断了由ACh诱导的所有电导状态。在相同实验条件下进行的生化分析表明，用环己酰亚胺对纤维进行长期处理会抑制[³H]亮氨酸掺入可沉淀蛋白。目前的研究结果提供了证据，表明肌肉去神经支配后烟碱型受体功能特性的改变可能在没有新转录的情况下发生。
