Control of Ciliary Beating of Schistosomal Miracidia

血吸虫毛蚴被许多纤毛完全覆盖。毛蚴纤毛的剧烈跳动是毛蚴卵孵化、游动和侵入中间螺的动力。本研究旨在探讨曼氏血吸虫毛蚴纤毛搏动的控制机制，虽然某些外界刺激会引起毛蚴纤毛搏动的变化，本研究探讨了渗透压对纤毛搏动的控制机制以及纤毛搏动在趋化性游泳活动中的可能变化，主要结果如下：毛蚴的孵化是由纤毛的剧烈跳动和蛋壳的膨胀共同作用引起的; 2）膜透性cAMP、Forskokin和IBMX引起毛蚴纤毛的跳动，毛蚴在高渗透压下保持安静。3)蛋白激酶A抑制剂和钾离子通道阻断剂抑制毛蚴在水中的纤毛搏动; 4）膜可透性cAMP而非膜可透性cAMP可使毛蚴产生类似趋化因子的特殊游泳活性毛蚴对蜗牛调理水（SCW）的（动力学）活性，5）毛蚴对SCW的趋化活性被雌二醇抑制，提示毛蚴纤毛搏动可能是毛蚴对SCW趋化活性的调控机制。毛蚴的体壁上有渗透压受体。当受体被低渗透压激活时，钾离子通道被激活。钾离子内流激活腺苷酸环化酶。然后cAMP浓度的增加激活微管运动，然后纤毛加热开始。当毛蚴暴露于高渗透压时，钾离子通道失活。cAMP浓度降低抑制纤毛搏动。趋化活性不受纤毛跳动的控制。

Schistosomal miracidia are completely covered by numerous cilia. The vigorous beating of cilia of miracidia is the driving force of hatching of the egg, swimming in water and invasion into the intermediate snail. The present study aimed at examination of the control mechanism of ciliary beating of miracidia of Schistosoma manosni.Although some external stimulus cause the change in the ciliary beating, the present study dealt with the control mechanism of ciliary beating by osmotic pressure and possible change of ciliaty beating in chemotactic swimming activity.The highlights of the results are 1) that hatching of the eggs is caused by the combination of vigorous beating of cilia and swelling of eggshell, 2) that membrane permeable cAMP, forskokin and IBMX cause the ciliary beating of miracidia which remain to he quiet under high osmotic pressure. 3) that protein kinase A inhibitor and potassium ion channel blocker suppress the ciliary beating of miracidia which swim in water, 4) that membrane permeable cAMP, but not non-permeable cAMP, cause miracidia to take peculiar swimming activity which mimic the chemotactic (klinokinetic) activity of miracidia to snail conditioned water (SCW), and 5) that chemotactic activity of miracidia to SCW is inhibited by eserine.Our results propose the possible control mechanism of ciliary beating of miracidia. Osmotic receptors are present over the integument of miracidia. When the receptors are activated by low osmotic pressure, potassium ion channel is activated. Influx of potassium ions activates adenyl cyclase. Then increase in cAMP concentration activates microtuble movement, then ciliary heating starts. When miracidia are exposed to high osmotic pressure, potassium ion channels are inactivated. Decrease in cAMP concentration suppress the ciliary beating. Chemotactic activity is not controlled by ciliary beating.