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

微小血吸虫对中间螺的排泄和分泌表现出趋化性，确切地说是趋化性。本研究旨在探讨由钉螺排泄/分泌引起的幼虫行为改变的信号转导，并探讨分泌幼虫引诱剂的钉螺的人口学特征。褐藻菌对蜗牛分泌趋化性的信号转导。建立了一种定性、定量地观察紫花苜蓿趋化活性的方法。Miracidia被允许在一个矩形玻璃管中自由游动。在试管末端注射等量0.5 ul的蜗牛分泌物，然后在录像带上记录miracidia的行为变化。本实验试图从药理学角度探讨蜗牛分泌物引起的微小动物行为改变的相关因素。膜透性|cAMP和IBMX诱导的行为变化类似于蜗牛分泌引起的行为变化。非膜透性CAMP和CGMP未引起任何变化。血清素引起了行为的改变。暴露于eserine的Miracidia对蜗牛分泌物没有趋化作用。这些结果表明CAMP参与了miracidia对钉螺的趋化作用，其行为变化是由肌肉收缩引起的。分泌诱虫剂的钉螺的人口统计学特征。研究了不同年龄、感染和未感染的钉螺的分泌活性，以及不同种类钉螺的中间宿主在不同年龄和感染情况下对血吸虫引诱剂的分泌情况。在非中间寄主的蜗牛中，有些蜗牛会分泌对血吸虫有强引诱作用的引诱剂。

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.