Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, 211#, Huimin Road, Chengdu, China.
Department of Aquaculture, College of Animal Science and Technology, Sichuan Agricultural University, 211#, Huimin Road, Chengdu, China; Chengdu Agricultural College, 392#, Detong Bridge Road, Chengdu, China.
Horm Behav. 2022 Jul;143:105199. doi: 10.1016/j.yhbeh.2022.105199. Epub 2022 May 18.
Previous data suggested that activation of endocannabinoid receptor 1 (CB1) was necessary for the orexigenic effect of Ghrelin in rodents, but the information is limited in teleosts. To investigate the feeding regulation pathway of Ghrelin and CB1 in Siberian sturgeon (Acipenser baerii), this study first identified the Ghrelin (345 bp, complete coding sequence) and Ghrelin receptor (GHSR, 500 bp, partial coding sequence) sequences, and then detected their tissue distribution patterns, which showed that Ghrelin is mainly distribution in peripheral tissues, while GSHR is mainly in different brain divisions. Besides, the qPCR before and after feeding showed that the mRNA expressions of Ghrelin and GHSR were inhibited after feeding in telencephalon, diencephalon and mesencephalon. Subsequently, the food intake and appetite factor expressions were measured by i.c.v. co-injection of Ghrelin and GSHR antagonist. The results showed that Ghrelin promoted the food intake of Siberian sturgeon, which was reversed by its receptor antagonist. Besides, i.c.v. injection of Ghrelin decreased telencephalon CART expression while increased NPY expression in the three brain regions. In addition, to further explore the relationship of Ghrelin and CB1 signal regulating feeding, the co-injection of Ghrelin and CB1 antagonists was performed. The results showed that AM6545 (CB1 peripheral restricted antagonist) failed to affect the orexigenic effect of Ghrelin and the expression pattern of NPY mRNA in the telencephalon. While in the diencephalon, the increase of food intake and NPY mRNA expression induced by Ghrelin was completely reversed by Rimonabant (CB1 global antagonist). These results indicate Ghrelin-GSHR pathway promotes the food intake of Siberian sturgeon by inducing the expression of NPY in the diencephalon, and the stimulating effect will be reversed by cannabinoid receptor antagonism. This study provides a foundation for understanding the pathways Ghrelin and CB1 signals in appetite regulation of the teleost.
先前的数据表明，内源性大麻素受体 1（CB1）的激活对于 Ghrelin 在啮齿动物中的食欲刺激作用是必要的，但在硬骨鱼类中的信息有限。为了研究 Ghrelin 和 CB1 在西伯利亚鲟（Acipenser baerii）中的摄食调节途径，本研究首先鉴定了 Ghrelin（345bp，完整编码序列）和 Ghrelin 受体（GHSR，500bp，部分编码序列）序列，然后检测了它们的组织分布模式，结果表明 Ghrelin 主要分布在外周组织中，而 GHSR 主要分布在不同的脑区。此外，摄食前后的 qPCR 显示，Ghrelin 和 GHSR 的 mRNA 表达在端脑、间脑和中脑摄食后受到抑制。随后，通过 i.c.v. 共注射 Ghrelin 和 GHSR 拮抗剂测量摄食和食欲因子表达。结果表明，Ghrelin 促进了西伯利亚鲟的摄食，其受体拮抗剂可逆转这一作用。此外，i.c.v. 注射 Ghrelin 降低了三个脑区端脑 CART 的表达，而增加了 NPY 的表达。此外，为了进一步探讨 Ghrelin 和 CB1 信号调节摄食的关系，进行了 Ghrelin 和 CB1 拮抗剂的共注射。结果表明，AM6545（CB1 外周受限拮抗剂）不能影响 Ghrelin 的食欲刺激作用和端脑 NPY mRNA 的表达模式。然而，在间脑，Ghrelin 诱导的摄食增加和 NPY mRNA 表达的增加完全被 Rimona-bant（CB1 全局拮抗剂）逆转。这些结果表明，Ghrelin-GHSR 途径通过诱导间脑 NPY 的表达促进西伯利亚鲟的摄食，而大麻素受体拮抗剂会逆转这种刺激作用。本研究为了解 Ghrelin 和 CB1 信号在鱼类摄食调节中的作用途径提供了基础。
