CILIARY BEATING OF SCHISTOSOMA MIRACIDIUM-POSSIBLE INVOLVEMENT OF CYCLIC NCLEOTIDE AND ION CHANNEL

草履虫纤毛运动调控的研究，促使我们进一步探讨微小血吸虫纤毛跳动的调控机制。本研究旨在探讨cAMP、cGMP、蛋白激酶A和离子通道可能参与血吸虫纤毛跳动的信号转导机制。寄生血吸虫依靠覆盖体表的大量纤毛在水中游动。miracidia在1% NaCL溶液中停止游动。加入膜透性cAMP或cGMP可使约40%的miracidia在高渗透压下游泳，但游泳速度约为miracidia在水中游泳的1/6。腺苷环化酶和鸟苷环化酶的活化剂福斯克林和磷酸二酯酶的抑制剂IBMX的加入也引起了微小的正向游动。这些试剂的作用是剂量依赖性的。霍乱毒素通过对g蛋白的作用增加后生动物腺苷环化酶活性。而霍乱毒素对小毛虫纤毛无明显影响。蛋白激酶A抑制剂H88和H89抑制水中微生物游动。K^+通道阻滞剂、奎宁和α树突素可引起miracidia在水中游动。H88、H89、奎宁和α树突毒素的抑制作用呈剂量依赖性。Na^+通道阻滞剂和Ca^<++>通道阻滞剂对水母游动无影响。这些结果表明，环核苷酸、蛋白激酶A和K^+通道对血吸虫纤毛节律有调节作用。

The studies on regulation of ciliary motility in Paramecium encouraged us to investigate the control mechanisms of ciliary beat of schistosome miracidia. The present study aimed at investigating the possible involvement of cAMP,cGMP,protein kinase A and ion channels in signal transduction mechanisms of ciliary beat of schistosome miracidia.Schistosome miracidia swim in water by means of numerous cilia which cover the body surface. The miracidia stop swimming in 1% NaCL solution. Addition of membrane permeable cAMP or cGMP causes about 40% of miracidia to swim under high osmotic pressure, the swimming speed is about 1/6 of that of miracidia swimming in water though. Addition of forskolin, an activator of adenyl cyclase and guanyl cyclase, and IBMX,an inhibitor or phosphodiesterase also caused miracidial forward swimming. The effect of these reagents was dose dependent.Cholera toxin increases adenyl cyclase activity of metazoan via tis effect on G-protein. However, cholera toxin did not have any effect on ciliary beat of miracidia. Inhibitor of protein kinase A,H88 and H89, inhibited miracidial swimming in water. K^+channel blocker, quinine and alpha dendrotixin, caused swimming of miracidia in water. Inhibitory effect of H88, H89, quinine and alpha dendrotoxin was dose dependent. Na^+channel blocker and Ca^<++>channel blocker did not have any effect on swimming of miracidia.These results suggest that cyclic nucleotide, protein kinase A and K^+channel regulate ciliary beat of schistosome miracidia.