Takai H, Morisawa M
Misaki Marine Biological Station, School of Science, University of Tokyo, Kanagawa, Japan.
J Cell Sci. 1995 Mar;108 ( Pt 3):1175-81. doi: 10.1242/jcs.108.3.1175.
We previously demonstrated that osmolality isotonic to the seminal plasma suppresses sperm motility in marine and freshwater teleosts, and exposure of sperm to hypertonicity of sea water or hypotonicity of fresh water, respectively, induces the initiation of sperm motility at spawning. The motile sperm became immotile by return of osmolality to the isotonic osmolality both in a marine teleost, the puffer fish, and a freshwater teleost, the zebrafish. The initiation and termination of sperm motility could be repeated several times by changing surrounding osmolality in both species. In demembranated sperm, motility was suppressed by a K+ concentration equivalent to the seminal salt concentration in both puffer and zebrafish. Demembranated puffer sperm were reactivated when K+ concentration of the reactivating solution increased. Conversely, initiation of motility in the demembranated zebrafish sperm was induced by decreasing K+ concentration. The initiation and termination of the demembranated sperm were alternately repeated by changing K+ concentration of the reactivation solution in both species. Furthermore, intracellular K+ concentration rose when sperm motility of the puffer was initiated in hypertonic solutions. These results suggest that change in external osmolality is converted into change in intracellular K+ concentration, and that the change affects the flagellar axoneme as a signal to initiate or terminate sperm motility. The initiation and termination of motility in the demembranated puffer sperm were caused at a high pH and a low pH of the reactivating solution, respectively, suggesting the contribution of intracellular pH in the regulation of flagellar motility.
我们之前证明，与精浆等渗的渗透压会抑制海洋和淡水硬骨鱼的精子活力，而精子分别暴露于海水的高渗或淡水的低渗环境中，则会在产卵时引发精子活力。在海洋硬骨鱼河豚和淡水硬骨鱼斑马鱼中，当渗透压恢复到等渗渗透压时，活动的精子都会变得不活动。通过改变两种鱼周围的渗透压，精子活力的启动和终止可以重复多次。在去膜精子中，河豚和斑马鱼的精子活力都受到与精浆盐浓度相当的钾离子浓度的抑制。当激活溶液中的钾离子浓度增加时，去膜的河豚精子会重新激活。相反，去膜斑马鱼精子活力的启动是由钾离子浓度降低诱导的。通过改变两种鱼激活溶液中的钾离子浓度，去膜精子的活力启动和终止可以交替重复。此外，当河豚精子在高渗溶液中开始运动时，细胞内钾离子浓度会升高。这些结果表明，外部渗透压的变化会转化为细胞内钾离子浓度的变化，并且这种变化作为启动或终止精子活力的信号影响鞭毛轴丝。去膜河豚精子活力的启动和终止分别是由激活溶液的高pH值和低pH值引起的，这表明细胞内pH值在鞭毛运动的调节中发挥作用。
