(1) The effect of tannic acid (TA), a dominant component of plant allelochemicals, was investigated on the locomotion and feeding of the pond snail, Lymnaea stagnalis. The effect of TA on the neuronal background underlying feeding activity was also analysed. (2) TA affected the spontaneous locomotion and of juvenile snails in a concentration-dependent way. Low (10 μM) TA concentration resulted in an increased (sliding or swimming) activity compared to the control; meanwhile, high (100 μM) TA concentration inhibited the locomotion of the animals. (3) Low (10 μM) TA concentration increased the frequency of sucrose-evoked feeding of intact animals, whereas high (100 μM) TA concentration resulted in significantly longer feeding latency and decreased feeding rate. The feeding changes proved to be partially irreversible, since after 48 h maintained in clear water, the animals tested in 100 μM TA previously still showed lower feeding rate in sucrose. (4) Electrophysiological experiments on semi-intact preparations showed that application of 100 μM TA to the lip area inhibited the fictive feeding pattern of central neurons, the cellular response to sucrose. (5) On isolated CNS preparation, 100 μM TA applied in the bathing solution, however, failed to inhibit the activation of the central feeding (CPG) interneurons following application of extracellular dopamine. Our results suggest that TA affects both afferent and efferent peripheral functions in Lymnaea. TA reduces feeding activity by primarily blocking feeding sensory pathways, and its negative effect on locomotion may imply sensory pathways and/or ciliary activity.

中文翻译：

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丹宁酸的化感化学物质通过抑制周边途径影响池蜗牛（Lymnaea stagnalis）的运动和摄食行为。

（1）研究了植物化感物质的主要成分单宁酸（TA）对池塘蜗牛Lymnaea stagnalis的运动和摄食的影响。还分析了TA对潜在的进食活动神经元背景的影响。（2）TA以浓度依赖的方式影响自发运动和幼体蜗牛。与对照相比，低（10μM）的TA浓度导致活动增加（滑动或游泳）；同时，高浓度（100μM）的TA抑制了动物的运动。（3）低（10μM）TA浓度会增加完整动物蔗糖诱发的进食频率，而高（100μM）TA浓度会导致更长的进食潜伏期并降低进食速度。喂养的变化被证明是部分不可逆的，因为在清水中保持48小时后，先前在100μMTA中测试的动物的蔗糖喂养率仍然较低。（4）半完整制剂的电生理实验表明，将100μMTA应用于唇缘会抑制中枢神经元的虚构进食模式，从而抑制细胞对蔗糖的反应。（5）在分离的中枢神经系统制剂中，在浴液中施加100μMTA，但是在施加细胞外多巴胺后未能抑制中央饲喂（CPG）中枢神经的激活。我们的研究结果表明，TA会影响大鼠的传入和传出外周功能lymnaea。TA主要通过阻断进食的感觉途径来降低进食活动，并且它对运动的负面影响可能暗示着感觉途径和/或睫状活动。