Kano M, Yamamoto M
J Cell Physiol. 1977 Mar;90(3):439-44. doi: 10.1002/jcp.1040900307.
The development of spike potential mechanisms during cell differentiation was studied in chick myotubes formed in vitro from trypsin-dissociated myoblasts. The spike potential and its rate of rise were measured in myotubes from 4-14 day old cultures. A depolarizing current pulse was delivered to evoke the spike potential after the steady membrane potential had been adjusted to a standard level of -80 mV in all cases. This gives the greatest maximum rate of rise of the spike potential and eliminates variation due to differences in the resting membrane potential of the myotubes. The size and maximum rate of rise of the spike potential increased significantly during the period examined. The spike potential was blocked by tetrodotoxin in almost all myotubes. These results suggest that during differentiation myotubes develop the ability to generate a spike potential due to an inward current carried by sodium ions.
利用胰蛋白酶解离的成肌细胞在体外形成鸡肌管，研究了细胞分化过程中峰电位机制的发育情况。在4至14日龄培养物的肌管中测量了峰电位及其上升速率。在所有情况下，将稳定的膜电位调整到-80 mV的标准水平后，施加去极化电流脉冲以诱发峰电位。这能使峰电位的最大上升速率达到最大，并消除因肌管静息膜电位差异而产生的变化。在所研究的时期内，峰电位的大小和最大上升速率显著增加。几乎所有肌管中的峰电位都被河豚毒素阻断。这些结果表明，在分化过程中，肌管由于钠离子携带的内向电流而具备产生峰电位的能力。
