Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Neuropeptides. 2020 Jun;81:102045. doi: 10.1016/j.npep.2020.102045. Epub 2020 Mar 19.
Substance P (SP) is an 11-amino acid tachykinin-related peptide that has anorexigenic effects in birds and mammals although the central mechanism is not well understood. Hence, the objective was to identify appetite-associated hypothalamic mechanisms in Japanese quail (Coturnix japonica). Seven days post-hatch, quail were intracerebroventricularly injected with 0, 0.25, 0.5 or 1.0 nmol of SP and monitored for 180 min. On a cumulative basis, quail that received 0.5 and 1.0 nmol of SP consumed less food for 90 min post-injection. On a non-cumulative basis, food intake was reduced in 0.5 nmol-injected birds at 30 min post-injection. Water intake was not affected. A comprehensive behavior analysis was performed, revealing that SP-injected chicks displayed less feeding pecks and reduced locomotion compared to vehicle-injected birds. To identify molecular mechanisms, the hypothalamus was isolated at 1 h post-injection and real-time PCR was performed to measure mRNA. Agouti-related peptide (AgRP) mRNA was reduced in SP-injected chicks. Immunohistochemistry was used to quantify c-Fos-expressing cells in appetite-associated hypothalamic nuclei. There were more reactive cells in the lateral hypothalamus (LH) and the paraventricular nucleus (PVN) of SP- than vehicle-injected chicks. The LH and PVN were collected for gene expression analysis. Corticotropin-releasing factor (CRF) and urotensin 2 (UTS2) mRNAs were greater in SP- than vehicle-injected chicks in the PVN. In the LH, CRF receptor sub-type 2 (CRFR2) mRNA was greater and kappa opioid receptor mRNA was reduced in SP- compared to vehicle-injected quail. Thus, SP induces a potent anorexia in quail that coincides with increased LH-specific CRFR2 mRNA and increased UTS2 mRNA in the PVN. Future studies will evaluate whether SP-induced anorexigenic effects are mediated through CRF receptors.
P 物质（SP）是一种 11 个氨基酸的速激肽相关肽，它对鸟类和哺乳动物具有厌食作用，尽管其中枢机制尚不清楚。因此，本研究的目的是确定日本鹌鹑（Coturnix japonica）下丘脑与食欲相关的机制。孵化后 7 天，鹌鹑经脑室内注射 0、0.25、0.5 或 1.0 nmol SP，并监测 180 分钟。累积基础上，接受 0.5 和 1.0 nmol SP 注射的鹌鹑在注射后 90 分钟内摄食量减少。非累积基础上，在注射后 30 分钟，接受 0.5 nmol 注射的鸟类的食物摄入量减少。水的摄入量没有受到影响。进行了全面的行为分析，结果显示 SP 注射雏鸡的啄食和运动减少。为了确定分子机制，在注射后 1 小时分离下丘脑，进行实时 PCR 测量 mRNA。SP 注射雏鸡的 AgRP mRNA 减少。用免疫组织化学定量分析与食欲相关的下丘脑核中 c-Fos 表达细胞。SP 注射雏鸡的外侧下丘脑（LH）和室旁核（PVN）中的反应性细胞更多。收集 LH 和 PVN 进行基因表达分析。PVN 中 SP 注射雏鸡的促肾上腺皮质释放因子（CRF）和尾加压素 2（UTS2）mRNA 高于载体注射雏鸡。在 LH 中，SP 注射鹌鹑的 CRF 受体亚型 2（CRFR2）mRNA 增加，而 κ 阿片受体 mRNA 减少。因此，SP 诱导鹌鹑产生强烈的厌食症，同时伴随着 LH 特异性 CRFR2 mRNA 增加和 PVN 中 UTS2 mRNA 增加。未来的研究将评估 SP 诱导的厌食作用是否通过 CRF 受体介导。
