Role of cAMP, cGMP and Ca++ in chemotaxis of Schistosome Miracidia

血吸虫毛蚴表现出趋化性，确切地说是趋动性，朝向中间螺的排泄/分泌。本研究旨在探讨钉螺排泄/分泌物引起的迷走行为变化的信号转导机制，以及分泌毛蚴引诱剂的钉螺的人口统计学特征.毛蚴对钉螺分泌物趋化作用的信号转导研究建立了定性、定量观察毛蚴趋化活性的方法。毛蚴被允许在矩形玻璃管中自由游动。取钉螺分泌物0.5 μ l注射器接种于试管末端，用录像带记录毛蚴的行为变化。本实验旨在探讨钉螺分泌物引起毛蚴行为改变的相关因素。渗透膜|cAMP和IBMX引起的行为变化类似于蜗牛分泌物引起的行为变化。非膜渗透性CAMP和CGMP没有引起任何变化。5-羟色胺引起行为改变。毛蚴对钉螺分泌物无趋化作用。这些结果表明，cAMP参与毛蚴对钉螺的趋化作用，毛蚴的行为变化是由肌肉收缩引起的.分泌毛蚴引诱剂的螺类的人口学特征本实验研究了不同年龄、感染与否的螺类分泌物的活性，以及不同种属的血吸虫中间宿主分泌毛蚴引诱剂的活性，与年龄和感染与否无关。在非中间宿主的螺类中，有些螺类能分泌强引诱剂。

Schistosoma miracidia show chemotaxis, exactly speaking klinokinesis, towards the excretion/secretion of the intermediate snails. The present study was attempted to examine the signal transduction of miradial behavior changes caused by the excretion/secretion of the snails and examine the demographic character of snails which secrete the attractant for miracidia.1. Signal transduction of chemotaxis of miradicia towards the secretion of snails.The method was developed to observe qualitatively and quantitatively the chemotactic activity of miracidia. Miracidia were allowed to swim free in a rectangular glass tube. An aliquot of 0.5 ul of secretion of snails was syringe inoculated at the end of tube, then the behavior changes of miracidia was recorded on the video tape. The experiments were attempted to examine pharmacologically the factors which are involved in the behavior changes of miracidia caused by the secretion of snails. The membrane permeable |cAMP and IBMX induced the behavior changes which mimic those caused by the secretion of snails. Non-membrane permeable CAMP and CGMP did not cause any change. Serotonin induced the behavior changes. Miracidia exposed to eserine did not show the chemotaxis towards the secretion of snails. These results suggest that CAMP is involved in the chemotaxis of miracidia towards the snails and the behavior changes are induced by the contraction of muscles.2. Demographic character of snails which secrete thp attractant for miracidia.The experiment was attempted to examine the aciivity of secretion of snails with different ages or with/without infection, and of different species of snailak Schistosome intermediate hosts secrete the attractant for miracidia regardless of age and infection by schistosome. Out of the snails which are not intermediate hosts, some snails secrete powerful attractant for schistosojoie.