雷公藤总生物碱对粘虫幼虫神经系统酶活性及神经递质含量的影响

【目的】明确雷公藤Tripterygium wilfordii Hook. f.生物碱对粘虫Mythimna separata (Walker)神经系统的影响，为阐明其杀虫作用机制提供依据。【方法】采用载毒叶片法测定粘虫5龄幼虫经雷公藤总生物碱处理后体内乙酰胆碱酯酶（AChE）、Na⁺, K⁺-ATPase、Ca²⁺, Mg²⁺-ATPase、谷丙转氨酶（GPT）和谷氨酸脱羧酶（GAD）等重要神经系统酶活性及乙酰胆碱（ACh）、谷氨酸（Glu）和γ-氨基丁酸（GABA）等神经递质的含量。【结果】雷公藤总生物碱处理对粘虫5龄幼虫AChE无明显影响，麻醉期处理粘虫幼虫体内ACh相对含量与同期对照无显著差异。处理粘虫幼虫在轻度麻醉期、深度麻醉期和复苏期体内GABA和Glu含量显著升高，GABA含量分别升高了89.86%, 49.28%和20.29%，Glu含量分别升高了24.55%, 23.33%和8.13%。处理粘虫幼虫GPT活性明显受到抑制，而GAD活性无明显变化。处理明显抑制粘虫幼虫头部Na⁺, K⁺-ATPase和Ca²⁺, Mg²⁺-ATPase活性，但对中肠两种ATPase活性影响不大。【结论】研究结果有助于了解雷公藤生物碱对昆虫神经系统的影响，也为进一步阐明其作用靶标奠定了基础。

Effects of total alkaloids from Tripterygium wilfordii (Celastraceae) on the activities of neural enzymes and contents of neurotransmitters in larval Mythimna separata (Lepidoptera: Noctuidae)

【Aim】 The objective of this research is to determine the effects of total alkaloids from Tripterygium wilfordii Hook. f. on insect nervous system and to provide a basis for elucidating its insecticidal mechanisms. 【Methods】 The 5th instar larvae of Mythimna separata (Walker) were fed with maize leaves treated with the total alkaloids from T. wilfordii. The activities of acetylcholine esterase (AChE), Na⁺, K⁺-ATPase, Ca²⁺, Mg²⁺ - ATPase, glutamic-pyruvic transaminase (GPT) and glutamic decarboxylase (GAD) in the 5th instar larvae of M. separata treated were determined at three different poisoning stages, and the contents of neurotransmitters including acetylcholine (ACh), γ-aminobutyric acid (GABA) and glutamic acid (Glu) were also assayed. 【Results】 The AChE activity in the 5th instar larvae of M. separata was not affected by the total alkaloids from T. wilfordii. The ACh contents in treated larvae in the weak paralysis stage and the deep paralysis stage were not significantly different from those of the corresponding two controls. The GABA contents in treated larvae increased by 89.86%, 49.28% and 20.29%, while the Glu contents increased by 24.55%, 23.33% and 8.13% in the weak paralysis stage, the deep paralysis stage and the recovery stage, respectively. The GPT activity in treated larvae was remarkably inhibited by the total alkaloids, but the GAD activity was not affected. The activities of Na⁺, K⁺-ATPase and Ca²⁺, Mg²⁺-ATPase in the brain of treated larvae were inhibited, but those in the midgut did not change. 【Conclusion】 The results help us understand the effects of the alkaloids from T. wilfordii on insect nervous system, and provide further scientific basis for revealing their action target.