Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2155, Japan.
J Endocrinol. 2010 Nov;207(2):185-93. doi: 10.1677/JOE-10-0081. Epub 2010 Aug 23.
We compared the central mechanisms of feeding suppression by the anorexigenic hormones neuromedin U (NMU) and neuromedin S (NMS) in rats. I.c.v. injection of either NMU or NMS dose dependently decreased 3-h food intake during the first quarter of a dark period. Pretreatment involving i.c.v. injection of a specific anti-NMS IgG blocked the suppression of food intake induced by i.c.v.- and i.p.-injected leptin, but anti-NMU IgG elicited no blockade. Quantitative PCR analysis revealed that i.c.v. injection of NMU or NMS caused a dose-dependent increase in CRH and proopiomelanocortin mRNA expression in the paraventricular nucleus (PVN) and arcuate nucleus (Arc) respectively. In tissue cultures of the Arc, secretion of α-melanocyte-stimulating hormone was stimulated by NMU and NMS, with more potent stimulation by NMS. The time-course curves of the increase in neuronal firing rate in Arc slices in response to NMU and NMS showed almost the same pattern, with a peak 10-15 min after treatment, whereas the time-course curves for the PVN slices differed between NMU and NMS. These results suggest that NMS and NMU may share anorexigenic effects, depending on physiological conditions.
我们比较了神经肽 U（NMU）和神经肽 S（NMS）这两种厌食激素对大鼠摄食抑制的中枢机制。脑室注射 NMU 或 NMS 均可剂量依赖性地减少暗期第 1 小时的食物摄入量。脑室预先注射特异性抗 NMS IgG 可阻断脑室和腹腔注射瘦素诱导的食物摄入抑制，但抗 NMU IgG 没有阻断作用。定量 PCR 分析显示，脑室注射 NMU 或 NMS 分别导致促肾上腺皮质激素释放激素和促肾上腺皮质激素原 mRNA 在室旁核（PVN）和弓状核（Arc）中的表达呈剂量依赖性增加。在 Arc 的组织培养中，NMU 和 NMS 刺激 α-促黑素细胞激素的分泌，而 NMS 的刺激作用更强。Arc 切片中对 NMU 和 NMS 反应的神经元放电率增加的时程曲线几乎相同，在治疗后 10-15 分钟达到峰值，而 PVN 切片中的时程曲线则在 NMU 和 NMS 之间存在差异。这些结果表明，NMS 和 NMU 可能具有厌食作用，这取决于生理条件。
