Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México , Mexico City, Mexico.
Departamento de Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas , Mexico City, Mexico.
Chronobiol Int. 2021 Feb;38(2):201-211. doi: 10.1080/07420528.2020.1858849. Epub 2021 Jan 4.
Circadian rhythms are an adaptive response of organisms to the environment that enables them to measure time. Circadian rhythms are some of the most studied biological rhythms. Serotonin (5HT) has been proposed as their modulator of circadian rhythms, playing a pivotal role in their establishment. However, 5HT concentrations are altered in insect organisms when they feed on some plant extracts. Insects show a variety of rhythms. The larval stage of the lepidopteran is a pest of economically important crops. As a response, plants have developed secondary metabolites, such as azadirachtin, obtained from . We assessed the circadian rhythm of 5HT in the brain and digestive tube of larvae of ; furthermore, the effect of extract on the oscillations was evaluated. 5HT modulates the rhythms of locomotor activity, and if extracts of alter the concentration of 5HT, it can indirectly alter the rhythms of locomotor activity, as well as peristaltic movements of the intestine. Larvae were exposed to a 12 h:12 h light-dark (LD) photoperiod, and half of them remained for 72 h under constant darkness (DD). Tissue samples were obtained at six different times during a single 24 h period, and the amount of 5HT was quantified by high-performance liquid chromatography (HPLC). Data were statistically compared by a one-way ANOVA followed by a Tukey test and subjected to Cosinor analysis for assessment of 24 h rhythmicity. The results showed that the methanolic extract had an effect on the 5HT concentration of the brain and digestive tube of the larvae. In the brain, the 5HT increase in larvae fed with the extract could alter memory, learning, sleep, and locomotor activity processes. Whereas in the intestine, the 5HT decrease in the larvae fed with the extract could decrease peristalsis movements and, therefore, indirectly influence the antifeedant effect.
昼夜节律是生物体对环境的适应性反应，使它们能够测量时间。昼夜节律是研究最多的生物节律之一。血清素（5HT）已被提议作为其昼夜节律的调节剂，在其建立中起着关键作用。然而，当昆虫以某些植物提取物为食时，其 5HT 浓度会发生变化。昆虫表现出多种节律。鳞翅目幼虫是经济上重要作物的害虫。作为一种反应，植物已经开发出次生代谢物，如印苦素，从 中获得。我们评估了幼虫大脑和消化道中 5HT 的昼夜节律；此外，还评估了 提取物对振荡的影响。5HT 调节运动活动的节律，如果 提取物改变 5HT 的浓度，它可以间接改变运动活动以及肠道的蠕动节律。幼虫暴露于 12 h：12 h 光暗（LD）光周期下，其中一半在连续黑暗（DD）下保持 72 h。在单个 24 h 期间的六个不同时间点获得组织样本，并通过高效液相色谱法（HPLC）定量 5HT 的量。数据通过单向方差分析进行统计比较，然后进行 Tukey 检验，并进行 Cosinor 分析评估 24 h 节律性。结果表明，甲醇提取物对幼虫大脑和消化道的 5HT 浓度有影响。在大脑中，提取物喂养的幼虫中 5HT 的增加可能会改变记忆、学习、睡眠和运动活动过程。而在肠道中，提取物喂养的幼虫中 5HT 的减少可能会减少蠕动运动，从而间接影响抗食作用。
