Metachronal wave of ciliary beats in a Paramecium cell.

原生动物的纤毛运动表现出异时协调，以保持相邻纤毛之间恒定的相位差。现在普遍认为，异时波是由细胞外液中相邻纤毛之间的流体动力学耦合引起的。为了证实这一点，我们计划在草履虫细胞的一个有限的部分打破纤毛运动的流体动力学耦合，并观察是否异时协调崩溃或不。我们用紫外线照射预先负载笼状钙离子的草履虫细胞的几个纤毛，以诱导限制性纤毛的节拍方向逆转。异时波通过纤毛运动方向被人为逆转的部分，这表明异时波是由细胞外液以外的介质介导的，为了阐明另一种介质，我们用两个微量吸管吸取草履虫细胞的两端，并施加一定频率的振动到其中一个微量吸管。这引起细胞体的周期性伸展。异时波的频率与周期性拉伸的频率相等。这些结果表明，细胞外液和细胞体都可以作为异时波传播的耦合介质。

Ciliary movements in protozoa show metachronal coordination so as to maintain a constant phase difference between adjacent cilia. This coordination is called as “metachronal wave”.It is now generally thought that metachronal waves arise from hydrodynamic coupling between adjacent cilia at extracellular fluid. To confirm this, we planed to breakdown the hydrodynamic coupling of ciliary movements at a restricted portion of a Parameciumcell and observe whether metachronal coordination collapses or not. We applied UV irradiation to several cilia of a Parameciumcell, which was loaded caged calcium beforehand, to induce the reversal of beat-direction of the restricted cilia. Metachronal waves passed over the portion where the direction of ciliary movements was artificially reversed, suggesting that metachronal wave is mediated by something other than extracellular fluid.To clarify the other mediator, we sucked both ends of a Parameciumcell by two micropipettes and applied a vibration with a certain frequency to the one of the micropipettes. This induced cyclic stretching of cell body. The frequency of metachronal wave became equal to that of the cyclic stretching. These results suggest that not only extracellular fluid but also cell body can act as a coupling medium for propagation of metachronal waves.