Electrophysiological responses of taste cells to nutrient mixtures in the polyphagous caterpillar of Grammia geneura
Electrophysiological responses of taste cells to nutrient mixtures in the polyphagous caterpillar of Grammia geneura
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DOI：
10.1007/s003590100191
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发表时间：
2001-04-01
影响因子：
2.1
通讯作者：
Chapman, RF
中科院分区：
文献类型：
--
作者：
Bernays, EA;Chapman, RF
在正常取食的昆虫中，味觉感受器暴露在复杂的化学混合物中，而不是单一的化合物。我们研究了在植物中出现的浓度的营养化合物的混合物对革兰氏毛虫毛虫的盖氏感受器的神经元的反应。刺激同一神经元的化合物在二元混合物中的作用通常是相加的。在含有刺激性化合物的混合物中，没有刺激作用的氨基酸通常不起作用，但谷氨酸降低了内侧感受器对丝氨酸的反应。刺激感受器中不同细胞的营养化合物相互独立地起作用。与来自三种寄主植物的游离氨基酸样品相似的复合氨基酸混合物，其摩尔浓度的刺激性低于预期。在寄主植物选择中，来自内感受器的反应可能由蔗糖主导；除非蔗糖水平较低，否则氨基酸对感觉输入的贡献很小，因为它们刺激与蔗糖相同的细胞。在侧感受器中，氨基酸的作用不依赖于糖。毛虫接触有限的化学感官阵列似乎不足以让它们根据游离氨基酸对植物进行细微的区分。
In a normally feeding insect, the taste receptors are exposed to complex mixtures of chemicals, not single compounds. We investigate the responses of neurons in the galeal sensilla of the caterpillar of Grammia geneura to mixtures of nutrient compounds at concentrations occurring in plants. Compounds that stimulated the same neuron were generally additive in their effects in binary mixtures. Amino acids that did not stimulate usually had no effect in mixtures with a stimulating compound, but glutamic acid reduced the response to serine in the medial sensillum. Nutrient compounds that stimulated different cells in a sensillum acted independently of each other. Complex mixtures of amino acids resembling samples of free amino acids from three host plants were less stimulating than expected from their molar concentrations. In host plant selection, the response from the medial sensillum is probably dominated by sucrose; unless sucrose levels are low, amino acids will contribute little to sensory input because they stimulate the same cell as sucrose. In the lateral sensillum, amino acids act independently of sugars. The limited contact chemosensory array of caterpillars seems inadequate to allow them to make fine distinctions between plants on the basis of their free amino acids.