Hubatsch D A, Jasmin B J
Department of Physiology, Faculty of Medicine, University of Ottawa, Ontario, Canada.
Am J Physiol. 1997 Dec;273(6):C2002-9. doi: 10.1152/ajpcell.1997.273.6.C2002.
We tested the hypothesis that acetylcholinesterase (AChE) expression in skeletal muscle cells is increased by passive mechanical stimulation. To this end, primary cultures of myotubes were subjected to repeated cycles of stretch-relaxation for 5 min, 30 min, 3 h, and 24 h, using the Flexercell FX-2000 strain unit. Although mechanical stimulation did not affect AChE expression at early time points, it led to a significant increase (42%; P < 0.05) in total AChE activity at 24 h. This increase reflected a general elevation in the activity of all AChE molecular forms as opposed to a preferential increase in a specific form. Tetrodotoxin (TTX) treatment did not prevent the increase in AChE expression, whereas nifedipine partially blocked it. These changes in enzyme expression were accompanied by increases in the levels of AChE mRNA, suggesting the involvement of pretranslational regulatory mechanisms. Together, these results illustrate that, in addition to neural activation and trophic factors, passive mechanical forces modulate expression of AChE in skeletal muscle cells. Because TTX did not prevent the increase in AChE expression, it appears that the effects of mechanical stimulation are independent of electrical activity, which further indicates the use of an alternate signaling pathway.
我们验证了一个假设，即被动机械刺激会增加骨骼肌细胞中乙酰胆碱酯酶（AChE）的表达。为此，使用Flexercell FX - 2000拉伸装置对肌管原代培养物进行5分钟、30分钟、3小时和24小时的反复拉伸 - 松弛循环。尽管在早期时间点机械刺激并未影响AChE的表达，但在24小时时总AChE活性显著增加（42%；P < 0.05）。这种增加反映了所有AChE分子形式活性的普遍升高，而非特定形式的优先增加。河豚毒素（TTX）处理并未阻止AChE表达的增加，而硝苯地平则部分阻断了这种增加。酶表达的这些变化伴随着AChE mRNA水平的升高，提示存在翻译前调控机制的参与。总之，这些结果表明，除了神经激活和营养因子外，被动机械力也能调节骨骼肌细胞中AChE的表达。由于TTX并未阻止AChE表达的增加，机械刺激的作用似乎独立于电活动，这进一步表明使用了另一种信号通路。
