华中农业大学大北农青年学者提升专项(2017DBN014); 武汉市青年科技晨光计划(2017050304010318); 现代农业产业技术体系专项资金(CARS-46)
College of fishery
为评估组氨酸和组胺对翘嘴鳜摄食调控的影响，对肉食性鱼类翘嘴鳜（Siniperca chuatsi）脑室注射（ICV）组氨酸及组胺，并用不同浓度组氨酸和组胺刺激鳜原代脑细胞，统计脑室注射后翘嘴鳜24h内的摄食量的变化，检测食欲基因和氨基酸感知信号通路的变化。结果显示，脑室注射组氨酸和组胺后翘嘴鳜的摄食量在12 h相比于对照组显著性下降，同时npy 、gcn2和atf4 mRNA的表达均显著降低（P<0.05），而agrp和mtor mRNA的表达却无显著性变化（P>0.05）。离体水平，与对照相比，1.0、2.0和3.0 mmol/L的组氨酸显著性抑制了npy mRNA 的表达（P<0.05），且随着浓度的升高，这种抑制作用会增强；同时，1.0和3.0 mmol/L的组氨酸也显著抑制了agrp mRNA 的表达（P<0.05），但不同浓度的组胺刺激并没有引起npy和agrp mRNA 的表达变化（P>0.05）。此外， 2.0 mmol/L的组氨酸刺激并不会引起鳜原代脑细胞mTOR信号通路下游关键蛋白S6的表达变化（P>0.05）。以上结果提示：组氨酸和组胺会抑制翘嘴鳜的食物摄入，组氨酸可能是通过激活鳜脑组胺神经元来发挥作用，而这种抑制作用可能是通过下调促食欲因子的表达来抑制翘嘴鳜的食物摄入量。
In the present study, the effects of histidine and histamine on food intake were evaluated through intraventricular (ICV) administration in Chinese perch (Siniperca chuatsi), and the primary cells of Chinese perch were stimulated with different concentrations of histidine and histamine. This study examined the food intake changes within 24 hours after ICV, and detected the changes of appetite genes and amino acid sensing signaling pathways. The results showed that histidine and histamine significantly decreased food intake at 12 h post-injection, compared with the control group. Meanwhile, the mRNA expression of npy, gcn2 and atf4 were significantly decreased (P<0.05), whereas the mRNA expression of agrp and mtor were no significant change (P>0.05). At the cellular level, compared with the control group, 1.0, 2.0 and 3.0 mmol/L of histidine obviously inhibited the expression of npy mRNA (P<0.05), and this inhibitory effect increased with increasing concentration; At the same time, 1.0 and 3.0 mmol/L of histidine also significantly inhibited the expression of agrp mRNA (P<0.05). In addition, different concentrations of histamine did not cause changes in npy and agrp mRNA expression (P>0.05). Besides, 2.0 mmol/L of histidine was no significant change the phosphorylation level of protein S6, as the downstream signaling of mTOR pathway. Our results suggest that histidine and histamine can inhibit the food intake of Chinese perch. Histidine suppresses food intake through its conversion into neuronal histamine, and the inhibitory effect of histidine and histamine on food intake might be mediated through down-regulating the expression of appetite-promoting genes.