Medina I R, Bregestovski P D
Institute of Experimental Cardiology, Cardiology Research Center of the U.S.S.R., Academy of Medical Sciences, Moscow.
Proc R Soc Lond B Biol Sci. 1988 Oct 22;235(1278):95-102. doi: 10.1098/rspb.1988.0064.
By using the patch-clamp technique, stretch-activated ionic channels were found in the membrane of cleaving freshwater fish embryos at the early stages of embryogenesis (2-256 cells). The application of negative pressure to the pipette increased the frequency of activation and the duration of bursts. This type of channel has a preferential K+ selectivity. When bathed on both membrane surfaces with 140 mM KCl the channel conductance was 71 pS. The kinetic behaviour did not depend markedly on either membrane potential (in the range from -70 to +70 mV) or calcium concentration on the cytoplasmic side of the membrane. On continuous recording, the probability of the channel being open was found to change periodically over a 5- to 20-fold range for different cells. These variations correlated with changes in resting potential and membrane conductance during the cell cycle. These results suggest that the oscillation of resting potential within the cell cycle is associated with the operation of stretch-activated ion channels.
通过使用膜片钳技术，在胚胎发育早期（2 - 256细胞阶段）的淡水鱼胚胎分裂细胞膜中发现了牵张激活离子通道。向吸管施加负压会增加激活频率和爆发持续时间。这种类型的通道具有优先的K⁺选择性。当膜的两侧都用140 mM KCl浸泡时，通道电导为71 pS。动力学行为并不明显依赖于膜电位（在-70至+70 mV范围内）或膜细胞质侧的钙浓度。在连续记录中，发现不同细胞中通道开放的概率在5至20倍的范围内周期性变化。这些变化与细胞周期中静息电位和膜电导的变化相关。这些结果表明，细胞周期内静息电位的振荡与牵张激活离子通道的运作有关。
