Centro de Investigación Mariña, Laboratorio de Fisioloxía Animal, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía, Universidade de Vigo, Vigo, Spain.
Departamento de Fisiología de Peces y Biotecnología, Instituto de Acuicultura Torre de la Sal, Instituto de Acuicultura Torre de la Sal - Consejo Superior de Investigaciones Científicas (IATS-CSIC), Castellón, Spain.
Front Endocrinol (Lausanne). 2023 Aug 24;14:1241019. doi: 10.3389/fendo.2023.1241019. eCollection 2023.
This study explored changes in brain serotonin content and activity together with hypothalamic neuropeptide mRNA abundance around feeding time in rainbow trout, as well as the effect of one-day fasting. Groups of trout fed at two (ZT2) and six (ZT6) hours after lights on were sampled from 90 minutes before to 240 minutes after feeding, while additional groups of non-fed trout were also included in the study. Changes in brain amine and metabolite contents were measured in hindbrain, diencephalon and telencephalon, while in the diencephalon the mRNA abundance of tryptophan hydroxylase (, ), serotonin receptors , and ) and several neuropeptides (, , , , ) involved in the control of food intake were also assessed. The results showed changes in the hypothalamic neuropeptides that were consistent with the expected role for each in the regulation of food intake in rainbow trout. Serotonergic activity increased rapidly at the time of food intake in the diencephalon and hindbrain and remained high for much of the postprandial period. This increase in serotonin abundance was concomitant with elevated levels of mRNA in the diencephalon, suggesting that serotonin might act on brain neuropeptides to promote a satiety profile. Furthermore, serotonin synthesis and neuronal activity appear to increase already before the time of feeding, suggesting additional functions for this amine before and during food intake. Exploration of serotonin receptors in the diencephalon revealed only small changes for gene expression of and receptors during the postprandial phase. Therefore, the results suggest that serotonin may play a relevant role in the regulation of feeding behavior in rainbow trout during periprandial time, but a better understanding of its interaction with brain centers involved in receiving and processing food-related signals is still needed.
本研究探讨了在摄食时间前后，虹鳟脑内 5-羟色胺含量和活性的变化，以及一天禁食的影响。研究中，在光照后 2 小时（ZT2）和 6 小时（ZT6）投喂的两组虹鳟在摄食前 90 分钟至摄食后 240 分钟之间进行采样，同时还包括了未投喂的虹鳟组。在脑桥、间脑和端脑测量了脑内胺和代谢物含量，而在间脑还评估了色氨酸羟化酶（、）、5-羟色胺受体（、和）以及几种参与摄食控制的神经肽（、、、、）的 mRNA 丰度。结果表明，间脑中的神经肽发生了变化，这与它们在调控虹鳟摄食中的预期作用一致。在间脑和脑桥中，摄食时 5-羟色胺活性迅速增加，在摄食后很长一段时间内仍保持高水平。这种 5-羟色胺丰度的增加伴随着间脑 mRNA 水平的升高，表明 5-羟色胺可能作用于脑内神经肽，促进饱食状态。此外，5-羟色胺的合成和神经元活性似乎在摄食前就已经增加，这表明这种胺在摄食前和摄食期间可能具有其他功能。在间脑探索 5-羟色胺受体时，仅发现基因表达在摄食后阶段对 受体和 受体的变化很小。因此，结果表明，5-羟色胺可能在虹鳟摄食行为调节中发挥重要作用，特别是在摄食前后，但仍需要更好地了解其与参与接收和处理与食物相关信号的脑中枢的相互作用。
