下丘脑室旁核外源性orexin-A对肥胖大鼠摄食的影响及NPY受体信号的调控

目的:探讨饮食诱导肥胖(DIO)大鼠神经肽Y(NPY)受体信号通路是否参与下丘脑室旁核(PVN)外源性注射食欲素A(orexin-A)对摄食和葡萄糖敏感(GS)神经元兴奋性的调控。方法:采用荧光免疫组织化学实验观察PVN中orexin-A受体(即食欲素1型受体,OX1R)和NPY受体Y5(NPY-5R)的表达;采用单细胞外放电记录观察orexin-A对PVN内GS神经元兴奋性的影响;分别于SD大鼠和DIO大鼠PVN埋置套管,经套管注射orexinA、OX1R拮抗剂SB-334867和NPY-5R拮抗剂CGP-71683,观察大鼠0~2 h和0~4 h摄食量。结果:DIO大鼠PVN中OX1R和NPY-5R的表达显著高于SD大鼠。Orexin-A抑制PVN内葡萄糖抑制性(GI)神经元,兴奋葡萄糖兴奋性(GE)神经元,但是orexin-A对GS神经元的兴奋或抑制效应可被NPY-5R拮抗剂CGP-71683部分阻断,且与SD大鼠相比,orexin-A对DIO大鼠PVN内GS神经元兴奋或抑制效应更加明显。PVN内注射orexin-A可增加SD大鼠和DIO大鼠摄食量。但是orexin-A诱导的促摄食效应被NPY-5R拮抗剂CGP-71683部分阻断。与SD大鼠相比,orexin-A诱导的促摄食效应在DIO大鼠中更加明显。结论:PVN内外源性注射orexin-A可能主要通过OX1R信号通路参与大鼠摄食和GS神经元兴奋性调控,NPY-5R信号也参与了该过程调控,在DIO大鼠中更敏感。     

肥胖大鼠下丘脑前增食欲素原表达降低

肥胖对人体的健康已构成严重威胁。增食欲素(orex-ins)A和B是2种主要由下丘脑分泌的神经肽,均来源于同一前体———前增食欲素原(prepro-orexin)的蛋白水解产物,通过功能性受体增食欲素受体-1和2(orexin receptor-1OX1R;orexin receptor-2 OX2R)参与摄食和能量代谢调节。本研究     

饮食诱导肥胖大鼠下丘脑CIS和SOCS-3的mRNA表达

观察饮食诱导肥胖(diet-induced obese,DIO)大鼠下丘脑细胞因子诱导的含SH2区域的蛋白(cytokine in-ducible SH2 containing protein,CIS)与细胞因子信号转导抑制因子-3(suppressor of cytokine signaling 3,SOCS-3)mRNA表达的变化.将雄性6周龄SD大鼠,随机分为基础饮食组和高脂饮食组,饲养9周后处死.采用RT-PCR技术检测下丘脑CIS mRNA与SOCS-3 mRNA表达,结果表明高脂组大鼠下丘脑CIS mRNA、SOCS-3 mR-NA表达水平显著高于基础饮食组(P＜0.05).提示CIS、SOC-3可能参与DIO大鼠肥胖的发病机制.     

谷氨酸钠诱导不孕大鼠肥胖无排卵机制探讨

目的探讨谷氨酸钠诱导大鼠肥胖后对其不孕的影响。方法给新出生雌性Wistar大鼠皮下注射谷氨酸钠,连续5d,以建立肥胖模型。观察神经肽Y(NPY)、瘦素受体(obR)及促性腺激素释放激素(GnRH)在其下丘脑弓状核的表达的变化;并测定血清雌二醇(E2)、睾酮(T)、瘦素(leptin)、卵泡刺激素(FSH)、黄体生成素(LH)的变化。结果80﹪的注射谷氨酸钠大鼠呈能量失衡致肥胖状态;血清E2、T、leptin水平较对照组明显升高(P<0.05),FSH、LH水平较对照组明显降低(P<0.05);下丘脑弓状核NPY表达较对照组增强(P<0.05),而obR及GnRH表达较对照组减弱(P<0.05)。结论谷氨酸钠诱导肥胖大鼠由于神经内分泌-代谢失调而引起GnRH水平降低,导致下丘脑-垂体-卵巢轴功能失调性无排卵而引起不孕。     

大鼠发情周期下丘脑中食欲素及其受体的变化

目的 观察大鼠发情周期各期下丘脑中食欲素及其受体(OX1R、OX2R)表达的变化,探讨食欲素对发情周期的可能调节作用.方法 通过竞争性逆转录多聚酶链式反应 (competitive RT-PCR)方法检测大鼠下丘脑中食欲素前体(Prepro-Orexin)、食欲素-A、OXIR和OX2R在发情周期各期的表达.结果 发情前期的OX1R mRNA表达水平明显高于发情后期,而prepro-OX和OX2R mRNA的表达各期间没有明显的不同.结论 食欲素可能通过结合OX1R调节促性腺激素释放激素和/或黄体生成素的分泌而参与排卵的发生.     

妊娠、分娩以及泌乳期大鼠下丘脑中食欲素及其受体表达的变化

目的 观察大鼠下丘脑中食欲素(Orexin)及其受体(OX1R、OX2R)在妊娠、分娩以及泌乳期表达的变化,以探讨Orexin与生殖功能之间的关系.方法 通过竞争性逆转录多聚酶链式反应(Competitive RT-PCR)和免疫组织化学方法测定大鼠下丘脑中Orexin前体(Prepro-OX)、Orexin-A、OX1R和OX2R在妊娠、分娩以及泌乳期的表达.结果 Orexin-A和OX1R阳性神经元主要分别存在于大鼠下丘脑外侧区(LHA)以及妊娠和泌乳期大鼠的下丘脑室旁核 (PVN)和视上核(SON).泌乳第1d的Prepro-Orexin mRNA和OX1R的表达水平明显高于妊娠后期和泌乳期.OX2R的表达在生殖各时期之间没有明显改变.结论 Orexin可能参与大鼠泌乳早期的生殖功能调节,下丘脑的PVN及SON可能是其重要的作用部位.     

orexin A和orexin 1型受体在新生大鼠与成年大鼠延髓分布的比较

本文研究orexinA(OXA)和orexin 1型受体(OX1R)在新生大鼠与成年大鼠延髓的分布及比较。新生(1～5d)和成年(6～8周)SD大鼠,取其延髓,采用免疫组织化学方法和图像分析技术,观察OXA和OX1R在新生与成年SD大鼠延髓的分布。结果显示,OXA免疫反应阳性纤维和OX1R免疫反应阳性细胞在新生和成年SD大鼠延髓内有广泛分布,主要分布在延髓腹外侧区(ventrolateralmedulla,VLM)和舌下神经核(hypoglossalnucleus,XII)。在这两个区域,新生大鼠组的OX1R免疫反应阳性细胞的相对光密度值均低于成年大鼠组(P<0.001)。结果表明随着大鼠发育成熟,OX1R表达水平增加,可能与其生理功能完善有关。OXA免疫反应纤维和OX1R免疫反应阳性细胞在延髓的VLM和XII的表达提示可能与心血管和呼吸等活动的调节有关。     

电针对单纯性肥胖大鼠无排卵机制的影响

目的:探讨电针对食源性肥胖大鼠排卵机制的影响.方法:将刚断乳雌性SD大鼠分为2组,正常组喂以普通饲料,高能饲料组给予高能饲料,筛选出肥胖不孕大鼠.检测血清雌二醇(E2)、睾酮(T)、瘦素(leptin)、卵泡刺激素(FSH)、黄体生成素(LH)的水平;观察神经肽Y(NPY)及促性腺激素释放激素(GnRH)在下丘脑弓状核...     

营养性肥胖大鼠的脂代谢紊乱与下丘脑中增食欲素A的表达分析

目的: 研究营养性肥胖大鼠下丘脑中增食欲素(orexin A)表达与脂代谢紊乱的规律。 方法: 高脂饮食诱导并评估营养性肥胖大鼠动物模型;采用化学发光免疫分析法和生化酶法测定大鼠血清胰岛素(Ins)、甘油三酯(TG)和总胆固醇(TC);应用实时定量PCR检测下丘脑组织中orexin A mRNA的表达规律。 结果: 大鼠高脂膳食饲养8周后,营养性肥胖大鼠的体重、体脂含量和Lee's指数均高于对照组,血清Ins增加约50％,TG和TC分别增加约94％和43％(P<0.05);营养性肥胖大鼠下丘脑中orexin A的mRNA表达减少约57 % (P<0.05), 且orexin A的表达量与Lee's指数、Ins、TG、TC呈显著负相关,相关系数分别为r=-0.798 (P<0.05)、r=-0.868(P<0.05)、r=-0.981(P<0.05)和r=-0.815(P<0.05)。结论: 在大鼠高脂膳食诱导的营养性肥胖过程中,下丘脑orexin A的低表达和脂代谢紊乱均与营养性肥胖的发生密切相关。     

营养性肥胖大鼠弓状核促性腺激素释放激素的表达变化以及对精子发生的影响

目的:探讨营养性肥胖大鼠弓状核神经肽Y(NPY)、瘦素受体(ob-R)及与生殖相关的促性腺激素释放激素(GnRH)表达变化以及对精子发生的影响.方法:免疫组织化学观察NPY、ob R及GnRH在肥胖模型组下丘脑弓状核的表达情况以及睾丸支持细胞雄激素结合蛋白(ABP)表达变化;流式细胞分析检测睾丸生精细胞周期的改变.并测定血清中瘦素、睾酮、卵泡刺激素(FSH)和黄体生成素(LH)的水平.结果:肥胖大鼠血清中瘦素水平较对照组明显升高,睾酮、FSH、LH水平较对照组明显降低;下丘脑弓状核NPY表达较对照组增强,ob-R及GnRH表达较对照组减弱,ABP表达较对照组减弱;肥胖大鼠S期细胞显著下降,G2/M期细胞的百分数明显增多.结论:营养性肥胖大鼠由于神经内分泌代谢失调而引起GnRH水平降低,导致下丘脑垂体睾丸轴功能失调引起睾丸间质细胞及支持细胞功能降低,致使精子发生障碍,可能导致不育.     

Feeding response of weanling zucker obese rats to cholecystokinin and bombesin

Zucker weanling obese rat meal size is greater than in lean litter-mates by 4 weeks of age, indicating a possible decreased sensitivity to satiety signals. Adult Zucker obese rats are less sensitive to the putative satiety signal octapeptide of cholecystokinin (OP-CCK) when injected after a normal intermeal interval. In these experiments were compared responses of Zucker lean and obese rats from 3–11 weeks of age to OP-CCK and bombesin (BBS), another recently reported putative satiety agent. Injection of 2.0 and 4.0 μg/kg OP-CCK in 4–5 week olds had no effect on food intake of obese rats while decreasing 60-min food intake in lean rats 29 and 28 percent, respectively. However, 8.0 μg/kg OP-CCK decreased food intake of obese and lean rats similarly, indicating decreased, rather than lack of, sensitivity in the obese. The doses of 2.0 and 4.0 μg/kg BBS decreased food intake similarly in the obese and lean rats, but 1.0 μg/kg, although having no effect in lean rats, increased food intake in obese rats approximately 17 percent. Thus, while Zucker obese weanling rats appear to be less sensitive to OP-CCK, shown to decrease food intake in lean rats, they appear to be equally sensitive to the satiety effect of similar doses of BBS, but at low doses BBS stimulated food intake in obese but not lean rats.     

低氧运动干预肥胖模型大鼠下丘脑Nesfatin-1和Ghrelin水平

文题释义：Ghrelin：是一种含有28个氨基酸残基的短肽，于1999年被发现，主要由胃底分泌，在下丘脑中也有表达，其可促进摄食、减少能量消耗和增加体质量，是目前发现的唯一促食欲激素。 Nesfatin-1：是一种由82个氨基酸组成的神经肽，于2006年被发现，具有减少摄食、调节能量平衡和减轻体质量的作用。 背景：均衡饮食和科学运动是公认的安全、有效且经济的体质量管理干预方式，但运动本身有时却提升了减肥者食欲，如果将低氧环境刺激和有氧运动干预结合，可能会收到最好的减质量效果。下丘脑作为机体调控摄食和能量平衡的中枢，其调控因子与肥胖症发病机制之间的关系备受关注。 目的：观察低氧或/和运动后肥胖大鼠下丘脑nesfatin-1和ghrelin水平变化，探讨低氧或/和运动影响机体摄食和体质量的神经内分泌机制。 方法：60只营养性肥胖SD大鼠均分为常氧安静组、常氧运动组、16.3%低氧安静组、16.3%低氧运动组、13.3%低氧安静组和13.3%低氧运动组，进行8周的低氧或/和运动干预。低氧环境采用低氧发生器分别营造体积分数为16.3%氧气和13.3%氧气环境，低氧干预组大鼠每天12 h在低氧环境中生活和运动；运动干预采用跑台运动方案(跑速20 m/min、坡度0°)，持续时间40 min，5 d/周。记录干预期大鼠体质量、摄食量，计算干预前后Lee’s指数，用ELISA试剂盒检测干预后大鼠下丘脑nesfatin-1和ghrelin水平。 结果与结论：①干预后大鼠体质量与Lee’s指数：单纯低氧环境刺激对大鼠体质量、Lee’s指数的影响没有单纯有氧运动刺激明显，而当低氧和运动结合时，其效果优于单一刺激；②干预期间大鼠日均摄食量：常氧安静组保持平稳，其余各组均减少，尤以16.3%低氧运动组、13.3%低氧运动组明显；③下丘脑nesfatin-1和ghrelin水平：低氧结合运动可影响大鼠下丘脑nesfatin-1水平，其中13.3%低氧运动组的nesfatin-1水平最高；单纯的运动或低氧均可影响大鼠下丘脑ghrelin水平，而单一运动刺激效果强于单一低氧刺激，当二者结合时降低效果更明显；④双因素方差分析：体质量和ghrelin水平受运动的影响，体质量、Lee’s指数和摄食量受氧气体积分数的影响，体质量、nesfatin-1和ghrelin水平受运动×氧气体积分数的影响；⑤结果表明，8周低氧运动可能通过影响肥胖大鼠下丘脑nesfatin-1与ghrelin水平来减少大鼠的摄食量，抑制其体质量增长，降低其Lee’s指数，但具体机制需待进一步研究。 ORCID: 0000-0002-1519-7825(范锦勤) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

A selective orexin-1 receptor antagonist, SB334867, blocks 2-DG-induced gastric acid secretion in rats

We have previously demonstrated that intracisternal orexin-A potently stimulated gastric acid secretion through the vagus nerve. Considering its stimulatory action on feeding, we hypothesized that orexin-A is a candidate mediator of cephalic phase gastric secretion. It has also been suggested that the stimulation of acid by central orexin-A may be mediated by orexin 1 receptor (OX1R) in the brain. In the present study, we tried to clarify whether endogenously released orexin-A in the brain indeed plays a physiological role in gastric secretion. To address the question, the effects of OX1R antagonist on gastric acid secretion was examined in rats. Intraperitoneal administration of SB334867, a specific OX1R antagonist, by itself did not change gastric acid secretion in pylorus-ligated conscious rats. Pretreatment with SB334867 in a dose of 10 mg/kg completely blocked the stimulated acid output by intracisternal orexin-A but not thyrotropin-releasing hormone, suggesting that SB334867 specifically blocked the action of orexin-A in the brain. 2-Deoxy-D-glucose (2-DG)-induced stimulation of gastric acid output was significantly blocked by pretreatment with intraperitoneal administration of SB334867. These results suggest that endogenously released orexin-A in the brain plays a vital role in central regulation of gastric secretion. Since 2-DG induces central glucoprivation as a hunger state, the present study furthermore supports the speculation that orexin-A may be an important molecule that triggers the cephalic phase gastric acid secretion.     

Effects of leptin and orexin-A on food intake and feeding related hypothalamic neurons

The lateral hypothalamic area (LHA) and the ventromedial hypothalamic nucleus (VMH) have historically been implicated in ingestive behavior, energy balance and body mass regulation. The LHA is more closely associated with the initiation of eating; whereas the VMH mediates the cessation of eating. The parvocellular part of the paraventricular nucleus (pPVN) is also included in the suppressing mechanism. Recently, two hypothalamic peptides, orexin-A and orexin-B, localized in the posterior and lateral hypothalamic perifornical region were discovered in the rat brain and they increase food intake. Leptin, a protein encoded by an obesity gene, expressed in adipose tissue and released into the blood also affects food intake. Orexin and leptin receptors have been localized in the LHA, pPVN, and VMH. The purpose of this study was to measure food intake in the rat in response to leptin and orexin-A; and to determine their electrophysiological effects on feeding related hypothalamic neurons. Results clearly show that leptin suppresses food intake whereas orexin-A increases food intake. These differences are associated with leptin and orexin-A modulatory effects on LHA, pPVN, and VMH glucose responding neurons. In the LHA, leptin inhibits a larger proportion of both glucose-sensitive neurons (GSNs) and non-GSNs. In the pPVN, leptin increases more GSNs in comparison to non-GSNs. Whereas in the VMH, leptin increases the activity of glucoreceptor neurons (GRNs) in comparison to non-GRNs. Orexin-A had opposite effects: increases activity of GSNs more than the non-GSNs in the LHA and significantly suppresses GRNs in the VMH. In the pPVN, orexin-A had no observable effects on neurons that have a low density of orexin 2 receptors. Results are discussed in terms of hypothalamic neural circuits that are sensitive to endogenous food intake inducing and reducing substances.