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.

中文翻译：

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黄芪中P物质的厌食作用

物质 P (SP) 是一种 11 个氨基酸的速激肽相关肽，在鸟类和哺乳动物中具有厌食作用，但其中心机制尚不清楚。因此，目的是确定日本鹌鹑（Coturnix japonica）与食欲相关的下丘脑机制。孵化后 7 天，鹌鹑脑室内注射 0、0.25、0.5 或 1.0 nmol SP 并监测 180 分钟。在累积基础上，接受 0.5 和 1.0 nmol SP 的鹌鹑在注射后 90 分钟内消耗的食物较少。在非累积基础上，注射 0.5 nmol 的禽类在注射后 30 分钟的食物摄入量减少。饮水量没有受到影响。进行了全面的行为分析，结果表明，与注射载体的鸡相比，注射 SP 的鸡表现出较少的啄食和减少的运动。为了确定分子机制，在注射后 1 小时分离下丘脑，并进行实时 PCR 以测量 mRNA。注射 SP 的小鸡的刺豚鼠相关肽 (AgRP) mRNA 减少。免疫组织化学用于量化食欲相关下丘脑细胞核中表达 c-Fos 的细胞。SP- 的外侧下丘脑 (LH) 和室旁核 (PVN) 中的反应细胞比注射载体的小鸡多。收集 LH 和 PVN 用于基因表达分析。促肾上腺皮质激素释放因子 (CRF) 和尿加压素 2 (UTS2) mRNA 在 SP- 中比在 PVN 中注射载体的小鸡更大。在 LH 中，与载体注射的鹌鹑相比，SP- 中 CRF 受体亚型 2 (CRFR2) mRNA 更大，κ阿片受体 mRNA 减少。因此，SP 在鹌鹑中诱导强烈的厌食症，这与 PVN 中 LH 特异性 CRFR2 mRNA 的增加和 UTS2 mRNA 的增加一致。未来的研究将评估 SP 诱导的厌食作用是否是通过 CRF 受体介导的。