神经肽Y及其受体Y1、Y2对痛觉调制的研究进展

神经肽Y（neuropeptide Y,NPY）是一种由36个氨基酸残基组成的肽类激素,属胰多肽家族,广泛分布于中枢及外周神经组织的神经元中。NPY主要参与摄食行为、心血管活动、垂体分泌等生理功能的调节。NPY还参与了痛觉调制。NPY受体有Y1、Y2、Y3、Y4、Y5和Y6六种亚型。目前对Y1受体和Y2受体的研究较多,显示Y1受体和Y2受体参与痛觉调制。但现在对NPY在痛觉中的具体作用机制还不清楚。该文对NPY及其Y1受体、Y2受体在痛觉调制中的作用作一概述。     

神经肽Y(NPY)的生理功能研究进展

神经肽Y(NPY)是机体内的一种重要且保守的神经递质,一般以前体形式存在,释放的有活性的NPY主要通过与其受体结合发挥作用。NPY受体包含了亚型Y1、Y2、Y3、Y4、Y5、Y6、Y7、Y8。Y1和Y2是NPY发挥收缩血管作用的关键受体;Y1、Y2和Y5是NPY调节动物摄食行为的关键受体;Y1、Y2和Y4是NPY调控动物焦虑、沮丧行为的必要受体。着重对NPY与其各种受体结合后如何行使动物的相关生理功能的情况进行了阐述。     

神经肽Y参与痛觉调制的研究进展

神经肽Y（NPY）是中枢神经系统内含量最多的神经肽之一,它参与机体多种生理活动。近年来,对不同痛模型中NPY作用的研究表明,NPY可能通过激活脊髓和脊髓上水平的Y1受体或拮抗背根节的Y2受体发挥镇痛作用,此类研究将为NPY及其受体激动剂在镇痛中的应用提供重要的理论基础。本文就NPY及其Y1、Y2受体在痛觉调制中的作用作一简要综述。     

神经肽Y_2受体对神经病理痛调制的研究进展

神经肽Y2受体（neuropeptideY2 receptor,NPY2R）是一种在很多生理及病理情况下广泛分布、表达于哺乳动物的G蛋白耦联受体。Y2受体在众多生理作用及疾病中发挥重要影响,通过神经肽Y在脊髓及脊髓以上水平的作用,Y2受体对神经病理痛的形成有密切联系。本文拟从Y2受体分子生物学基础、相关的作用机制及涉及神经病理痛实验研究方面,就Y2受体对痛觉调制中的作用作简单综述。     

克隆的P2受体亚型的药理学研究进展

细胞外嘌呤（腺苷,ADP,ATP）及嘧啶（UDP,UTP）为重要的信使分子,通过细胞表面P2受体介导产生不同的生物效应,P2嘌吟受体的概念于1978年被提出,随后根据药理学特征又被分为P2X及P2X嘌呤受体,90年代,采用分子生物学手段,一系列配体门控的P2X受体及G蛋白耦联的P2Y受体被克隆及功能表达,迄今为止,已有七型P2X受体亚型（P2X1－7）及六型P2Y受体亚型被克隆（P2Y1,2,4,6,11,12）,各型具有不同的分子结构,药理学特征及组织分布,本文还讨论了目前可用于区分各亚型激动剂及拮抗剂。     

海马NMDA受体与神经肽Y在慢性应激性抑郁发生中的作用及其关系

本文旨在探讨N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体与神经肽Y(neuropeptide Y,NPY)在慢性应激抑郁发生中的作用与关系。建立慢性不可预见性温和应激(chronic unpredictable mild stress,CUMS)抑郁模型,海马单侧分别微量注射非竞争性NMDA受体拮抗剂MK-801、NPY-Y1受体阻断剂GR231118和NMDA后,利用体重测量及糖水偏爱测试、强迫游泳及敞箱实验等方法观察动物行为变化,运用免疫组织化学方法检测海马CA3区和齿状回(dentate gyrus,DG)内NPY的表达。结果显示,CUMS组大鼠表现出抑郁样行为变化,海马NPY表达显著降低;海马微量注射NMDA或NPY-Y1受体阻断剂GR231118,动物行为学表现均与CUMS组相同,注射NMDA可使NPY表达显著降低;海马微量注射MK-801能明显改善应激引起的抑郁样行为表现,并使海马NPY表达增加。联合注射GR231118与MK-801后,GR231118可以显著减弱MK-801的抗抑郁样行为的效应。以上结果表明,CUMS可能使谷氨酸(glutamic acid,Glu)过量释放,NMDA受体过度激活,抑制NPY表达,导致抑郁发生。NPY抗抑郁作用主要是通过NPY-Y1受体实现。     

中脑导水管周围灰质内微量注射神经肽γ减弱慢性神经痛大鼠对伤害性刺激的反应

探讨神经肽Y(neuropeptide Y,NPY)在SD大鼠中脑导水管周围灰质(periaqueductal grey,PAG)对伤害性刺激反应的作用。应用热板和机械压力实验法,以大鼠后爪缩爪反应潜伏期(paw withdrawal latency,PWL)为痛阈指标。观察PAG内微量注射NPY对PWLS的影响。PAG内注射0．05、0．1、0．2nmol NPY均显著地增加慢性神经痛大鼠的双侧PWLS,且呈量效关系。NPY引起的PWLs增加可被Y1受体拮抗剂和阿片受体拮抗剂所阻断。结果提示,在大鼠PAG微量注射NPY可产生明显的镇痛作用。     

神经肽Y及其受体在银屑病慢性瘙痒中的表达特征

该文旨在研究神经递质神经肽Y(NPY)及其受体在银屑病小鼠的背根神经节(DRG)与脊髓中的表达特征。将8周龄的雄性C57BL/6小鼠随机分为咪喹莫特(IMQ)模型组和空白对照组两组。观察小鼠的行为学变化和皮肤炎症,采用HE染色分析皮肤炎症,甲苯胺蓝染色分析肥大细胞浸润情况。通过实时荧光定量PCR分析DRG中NPY mRNA的表达变化和皮肤中细胞因子的表达变化,并通过RNA原位杂交技术分析Npy1r(NPY受体Y1相应的基因)、Npy2r(NPY受体Y2相应的基因)的表达情况。鞘内注射Y1拮抗剂或Y2拮抗剂后观察小鼠的行为学变化。IMQ造模小鼠的抓挠行为极显著增加。与对照组相比, IMQ模型组小鼠皮肤出现明显的银屑病样炎症性皮肤病变,而肥大细胞数目并无明显变化。在皮肤中, IMQ模型组IL-4与IL-5 mRNA表达水平与对照组相比没有明显改变;TSLP与IL-33表达水平升高。在DRG中, IMQ模型组NPY的m RNA表达水平与对照组相比升高, Npy2r与Nppb在神经元中有明显的共表达。在脊髓中, Npy1r与Grp有部分共表达, Npy1r与Npy2r同时表达在部分神经元中。在...     

脂肪细胞Npy4r促进高脂饮食诱导肥胖

脂肪组织的神经支配与调节在能量代谢稳态的维持中发挥重要作用。神经肽Y(neuropeptide Y, NPY)及其脂肪细胞受体信号通路促进高脂饮食诱导的肥胖,其中NPY受体1(NPY receptor Y1,NPY1R)与受体2(NPY2R)是主要的NPY外周受体。NPY受体4(NPY4R)也在脂肪组织表达,然而尚不清楚其是否参与肥胖的发生发展机制。本研究建立了NPY及其受体的免疫荧光成像技术和脂肪细胞回复性表达Npy4r小鼠。根据对不同部位脂肪组织的荧光显微术观察,发现NPY在肩胛间棕色脂肪和皮下脂肪的围绕血管区域以点状形式表达,NPY系统的各受体在脂肪组织的空间分布上具有明显的组织特异性：NPY1R在棕色脂肪、主动脉周围脂肪和性腺脂肪较为富集,NPY2R在棕色脂肪和主动脉周围脂肪较为富集,NPY4R在棕色脂肪与性腺脂肪较为富集。继而通过比较脂肪细胞回复性表达Npy4r小鼠与全身Npy4r基因静默小鼠在高脂喂食下的体重与糖代谢,发现脂肪细胞Npy4r促进高脂饮食诱导的肥胖(P <0.0001)。本研究明确了NPY及其受体NPY1R、 NPY2R和NPY4R在不同部位脂肪组织的蛋...     

神经肽受体Y5亚型在大鼠胃的表达

应用RT—PCR、Western印迹和免疫组化技术研究神经肽受体亚型Y5在正常大鼠和胃轻瘫大鼠胃的表达,并进行组织学定位。发现Y5受体在大鼠胃存在着表达,主要表达定位在胃窦的黏膜层,可能与胃动力的调控有关。半定量分析显示胃轻瘫大鼠较正常大鼠表达水平下调。     

Regulation of Neuropeptide Y Release by Neuropeptide Y Receptor Ligands and Calcium Channel Antagonists in Hypothalamic Slices

Neuropeptide Y (NPY) is an important regulator of energy balance in mammals through its orexigenic, antithermogenic, and insulin secretagogue actions. We investigated the regulation of endogenous NPY release from rat hypothalamic slices by NPY receptor ligands and calcium channel antagonists. High-potassium stimulation (60 mM) of the slices produced a calcium-dependent threefold increase in NPY release above basal release. The Y2 receptor agonists NPY(13-36) and N-acetyl[Leu28,Leu31]NPY(24-36), the Y4 agonist rat pancreatic polypeptide (rPP), and the Y4/Y5 agonist human pancreatic polypeptide (hPP) significantly reduced both basal and stimulated NPY release. NPY(13-36)-induced reduction of NPY release could be partially prevented in the presence of the weak Y2 antagonist T4-[NPY(33-36)]4, whereas the hPP- and rPP-induced inhibition of release was not affected by the Y5 antagonist CGP71683A or the Y1 antagonist BIBP3226. The selective Y1, Y2, and Y5 antagonists had no effect on either basal or potassium-stimulated release when administered alone. The calcium channel inhibitors omega-conotoxin GVIA (N-type), omega-agatoxin TK (P/Q-type), and omega-conotoxin MVIIC (Q-type) all significantly inhibited potassium-stimulated NPY release, without any effect on basal release, whereas nifedipine had no effect on either basal or stimulated release. Addition of both omega-conotoxin GVIA and omega-agatoxin TK together completely inhibited the potassium-stimulated release. In conclusion, we have demonstrated that NPY release from hypothalamic slices is calcium-dependent, involving N-, P-, and Q-type calcium channels. NPY release is also inhibited by Y2 agonists and rPP/hPP, suggesting that Y2 and Y4 receptors may act as autoreceptors on NPY-containing nerve terminals.     

Extensive Alternative Splicing in the 5'-Untranslated Region of the Rat and Human Neuropeptide Y Y5 Receptor Genes Regulates Receptor Expession

Neuropeptide Y (NPY) elicits a plethora of physiological effects by interacting with several distinct G protein-coupled receptors. Activation of one of these receptors, the NPY Y5 receptor, is thought to result in increased food intake, anticonvulsant effects, attenuation of opiate withdrawal, inhibition of neuronal activity, and alteration of renal function. Several alternatively spliced human and rat NPY Y5 receptor cDNAs have been isolated that use different combinations of exons in the 5'-untranslated region. The various human NPY Y5 receptor cDNAs appear to be differentially expressed in different brain regions. The level of human NPY Y5 receptor expressed transiently in COS1 cells was significantly influenced by the sequence of the 5'-untranslated region. These results indicate that alternative splicing in the 5'-untranslated region of the human and rat NPY Y5 receptor genes occurs in a tissue-specific manner and is one mechanism by which cells control the level of NPY Y5 receptor expression.     

Modeling of Neuropeptide Receptors Y1, Y4, Y5, and Docking Studies with Neuropeptide Antagonist Analogues: Implications for Selectivity

Abstract

Neuropeptide Y (NPY), receptors belong to the G-protein coupled receptor superfamily. NPY mediates several physiological responses, such as blood pressure, food intake, sedation. These actions of NPY are mediated by six receptor subtypes denoted as Y₁-Y₅ and y₆. Modeling of receptor subtypes and binding site identification is an important step in developing new therapeutic agents. We have attempted to model the three NPY receptor types, Y1, Y4, and Y5 using homology modeling and threading methods. The models are consistent with previously reported experimental evidence. To understand the interaction and selectivity of NPY analogues with different neuropeptide receptors, docking studies of two neuropeptide analogues (BVD10 and BVD15) with receptors Y1 and Y4 were carried out. Results of the docking studies indicated that the interaction of ligands BVD10 and BVD15 with Y1 and Y4 receptors are different. These results were evaluated for selectivity of peptide analogues BVD10 and BVD15 towards the receptors.     

Neuropeptide Y Y5-receptor activation on breast cancer cells acts as a paracrine system that stimulates VEGF expression and secretion to promote angiogenesis

Accumulating data implicate a pathological role for sympathetic neurotransmitters like neuropeptide Y (NPY) in breast cancer progression. Our group and others reported that NPY promotes proliferation and migration in breast cancer cells, however the angiogenic potential of NPY in breast cancer is unknown. Herein we sought to determine if NPY promotes angiogenesis in vitro by increasing vascular endothelial growth factor (VEGF) expression and release from 4T1 breast cancer cells. Western blot analysis revealed that NPY treatment caused a 52 ± 14% increase in VEGF expression in the 4T1 cells compared to non-treated controls. Using selective NPY Y-receptor agonists (Y1R, Y2R and Y5R) we observed an increase in VEGF expression only when cells were treated with Y5R agonist. Congruently, using selective Y1R, Y2R, or Y5R antagonists, NPY-induced increases in VEGF expression in 4T1 cells were attenuated only under Y5R antagonism. Endothelial tube formation assays were conducted using conditioned media (CM) from NPY treated 4T1 cells. Concentration-dependent increases in number of branch points and complete endothelial networks were observed in HUVEC exposed to NPY CM. CM from Y5R agonist treated 4T1 cells caused similar increases in number of branch points and complete endothelial networks. VEGF concentration was quantified in CM (ELISA) from agonist experiments; we observed a 2-fold and 2.5-fold increase in VEGF release from NPY and Y5R agonist treated 4T1 cells respectively. Overall these data highlight a novel mechanism by which NPY may promote breast cancer progression, and further implicate a pathological role of the NPY Y5R.     

The antiparallel pancreatic polypeptide fold in the binding of neuropeptide Y to Y1 and Y2 receptors

Neuropeptide Y (NPY) belongs to the pancreatic polypeptide fold (PP-fold) family of regulatory peptides. Analysis of circular dicroic spectra of NPY showed that it has a high degree of secondary structure in aqueous solution which is in agreement with the globular, folded crystal structure of PP. Using three different approaches with synthetic peptides, we have probed the importance of the PP-fold structure in the interaction of NPY with two types of binding sites, Y1 and Y2 receptors. First, stepwise construction of the NPY molecule from the C-terminal amidated end, showed that although C-terminal fragments encompassing most of the long alpha-helix reacted reasonably well with the Y2 receptor, both Y1 and Y2 receptors required the presence of both ends of the PP-fold for full activity. Second, perturbation of the PP-fold by substitution with a helix-breaking proline residue, resulted in the loss of recognition of the N-terminal segment of the molecule by both types of receptors. Finally, a hybrid analog was constructed in which the essential, but by itself inactive, C-terminal segment of NPY was joined with the PP-fold motif of PP. This segment of PP is only 43% homologous to the similar motif in NPY, and most of the common residues cluster in the hydrophobic core of the fold. Nevertheless, the hybrid analog reacted with almost full potency on the Y2 receptors. It is concluded that the antiparallel PP-fold is of structural importance for the receptor binding of NPY, and that its main function is to present the combined C- and N-terminal segments of the molecule to the receptors.