Melatonin inhibits reproductive activity through changes of serotonergic activity in the brain of freshwater catfish (Mystus cavasius)
Melatonin inhibits reproductive activity through changes of serotonergic activity in the brain of freshwater catfish (Mystus cavasius)
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DOI：
10.1016/j.aquaculture.2020.735378
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发表时间：
2020-09-15
期刊：
影响因子：
4.5
通讯作者：
Shahjahan, Md
中科院分区：
文献类型：
--
作者：
Badruzzaman, Muhammad;Ikegami, Taro;Shahjahan, Md
鱼类通过松果体和视网膜等感觉器官感知环境信号，并将其转化为内部刺激，激活被称为脑-垂体-性腺(BPG)轴的内分泌网络，启动和终止性腺发育。在本研究中，我们研究了光周期和褪黑素对淡水鲶鱼(Mystus Caasius)5-羟色胺能活动和性腺发育的影响。在中性光周期(L 12：12D)下饲养鱼类，5-羟色胺(5-HT)、5-羟基吲哚乙酸(5-HIAA)和5-HIAA/5-HT白天升高，夜间下降。当鱼适应恒定的光(LL)条件时，观察到类似的变化，而当鱼适应恒定的黑暗(DD)时，几乎没有变化。在含褪黑激素的水中饲养，6h内全脑5-羟色胺、5-羟色胺和5-羟色胺/5-羟色胺的含量显著降低，含褪黑激素的饲料处理显著降低鱼性腺指数和5-羟色胺能活性。在对照鱼的卵巢中观察到发育良好的卵黄生成卵母细胞，而在褪黑素处理的鱼中没有观察到。这些结果表明，光周期通过外界光刺激引起的褪黑素的振荡改变了古尔沙鱼脑中的5-羟色胺能活动。此外，对卵巢发育的抑制作用是由5-羟色胺-褪黑素系统的功能相互作用控制的。
Fish perceive environmental cues through sensory organs like the pineal gland and retina, and transduce them as internal stimuli to activate an endocrine network known as the brain-pituitary-gonadal (BPG) axis to initiate and terminate gonadal development. In the present study, we examined the influences of photoperiod and melatonin on serotonergic activity and gonadal development in an Indian the freshwater catfish, known as gulsha (Mystus cavasius). When fish were reared under a neutral photoperiod (12 L:12D), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA, a metabolite of 5-HT) and 5-HIAA/5-HT increased during the day and decreased at night. Similar changes were observed when fish acclimated to constant light (LL) conditions, whereas almost no changes occurred when fish were acclimated to constant darkness (DD). When fish were kept in water containing melatonin, a significant reduction of 5-HT, 5-HIAA and 5-HIAA/5-HT occurred in the whole brain within 6 h. Melatonin-containing feed treatment significantly lowered the gonadosomatic index and serotonergic activity of fish. Well-developed vitellogenic oocytes were observed in the ovaries of control fish, but not in melatonin-treated fish. These results indicate that photoperiod alters serotonergic activity in the brain of gulsha fish through the oscillations in melatonin caused by external photic stimuli. In addition, inhibitory effects on ovarian development are controlled by functional interactions of the serotonin-melatonin system.