海人酸诱导癫痫大鼠齿状回神经肽Y能苔状纤维侧枝发芽

目的：探讨海马苔状纤维侧枝发芽与癫痫发作敏感性形成的关系。材料与方法：在海人酸诱发大鼠出现癫痫发作后,采用免疫组织化学染色法观察大鼠海马齿状回内神经肽Ｙ能纤维的异常发芽。结果：首次证实在癫痫发作后７天时,在海马齿状回内分子层就已出现神经肽Ｙ能纤维的异常增生。结论：这可能是对癫痫发作后齿状回门区神经肽Ｙ能神经元缺失的一种代偿性变化。     

自发性高血压大鼠组织和体液中神经肽Y含量的变化

神经肽Ｙ（ｎｅｕｒｏｐｅｐｔｉｄｅＹ,ＮＰＹ）是１９８２年Ｔａｔｅｍｏｔｏ等首先在猪脑中发现并提纯的一种生物活性多肽。它与去甲肾上腺素（ＮＥ）共存于交感神经的末梢内,且常与ＮＥ共同释放,两者作用类似,ＮＰＹ并能增强ＮＥ的缩血管作用。一般认为,ＮＰＹ可...     

持续癫痫大鼠行为学和神经肽Y mRNA表达的改变

目的探讨癫痫持续状态（SE）对大鼠情感行为和学习记忆功能的影响及海马组织神经肽Y（NPY）mRNA的表达变化。方法戊四氮诱导大鼠SE，采用抬高迷宫和Morris水迷宫观察大鼠情感反应和学习记忆功能的改变。反转录多聚酶链反应（RT-PCR）方法检测大鼠海马NPYmRNA的表达。结果SE组大鼠在抬高迷宫开放臂中逃避时间延长（P〈0．01），进入次数增多（P〈0．01）；水迷宫中逃避潜伏期延长（P〈0．01），搜寻策略变差（P〈0．05），平台象限游泳时间百分比降低（P〈0．01），穿越平台次数减少（P〈0．01）。同时伴有海马NPYmRNA表达上调（P〈0．05）。结论SE可使大鼠情感行为改变和学习记忆功能受损，NPY可能参与这一变化的病理生理过程。     

大鼠腮腺内神经肽Y免疫组织化学观察

目的：观察大鼠腮腺内神经肽Y的分布。方法：免疫组织化学ABC方法。结果：腮腺纹状管和小叶间导管上皮细胞呈神经肽Y免疫反应阳性,免疫反应物分布于胞质,胞核为阴性反应。结论：大鼠腮腺导管上皮细胞内含有神经肽Y,其存在对调节腮腺分泌活动及局部血流具有一定意义。     

神经肽Y在癫痫发病机制中的作用

Neuropeptide Y (NPY) is a pancreatic polypeptide- related peptide, consisting of 36 amino acids. NPY is expressed in the nervous system widely and abundandy, mainly in the hippcampus, regulates the excitability of neurons through its receptors (Y1, Y2, Y5). In recent yeats the research progress indicated the changes induced by seizures in the level and distribution of NPY, its receptors subtypes and their respectire mRNAs in brain. The inhibitory action of NPY on glutamate- mediatedand in seizure phenomena, suggests that one of its roles in hippocampal physiology is to modulate neuronal excitability by regulating glutamate release.     

神经肽Y—Y1受体样免疫反应物质在大鼠中枢神经系统的分布

为探明神经肽Ｙ受体在中枢神经系统的分布，用免疫组织化学方法，研究了ＮＰＹ－Ｙ１受体亚型免疫反应神经细胞及纤维在大鼠中枢神经系统的分布。     

大鼠神经肽Y前体融合蛋白在大肠杆菌中的超表达

应用逆转录－聚合酶链式反应（ＲＴ－ＰＣＲ）从大鼠腋组织钓得神经肽Ｙ（ＮＰＹ）ｃＤＮＡ编码区序列。经ＤＮＡ序列测定证实其准确性后，将该ｃＤＮＡ定向亚克隆入一大肠杆菌的表达载体ｐＭＡＬ－Ｃ＿２的果糖结合蛋白（ＭＢＰ）基因中。ＤＮＡ测序表明ＮＰＹｃＤＮＡ与表达载体中ＭＢＰ开放阅读框架一致。将重组质粒转入大肠杆茵ＤＨ５α菌系中，该重组大肠杆菌在液体ＬＢ培养基中经１ｍｍｏｌ／Ｌ终浓度的ＩＰＴＧ诱导４ｈ，所表达的ＮＰＹ－ＭＢＰ融合蛋白产量高达大肠杆菌总蛋白量的６０％～７０％。超表达的ＮＰＹ经纯化后将为进一步进行结构与功能研究提供材料来源。     

高脂血症对大鼠大脑皮质神经肽Y能神经元的影响

目的观察高脂血症对大鼠大脑皮质神经肽Y(neuropeptide Y,NPY)能神经元的影响。方法雄性SD大鼠60只,随机分为实验组和对照组(n=30)。实验组饲以高脂饲料,于高脂饲料喂养7d、30d、90d后取大脑组织行免疫组化染色,显微图像分析。结果与正常对照组相比,高脂饲料喂养30d和90d后,大鼠血清总胆固醇浓度显著升高,NPY免疫阳性神经元数目和光密度增加(p<0.05),90d显著增加(p<0.01)。结论高脂血症时,NPY在大鼠大脑皮质过表达。     

癫痫大鼠海马内凋亡神经元超微结构的研究

目的　为揭示海人酸癫痫模型海马内神经元的死亡机制。　方法　选用海人酸诱导的癫痫大鼠模型,对海马内凋亡神经元的超微结构进行观察。　结果　电镜下,实验组大鼠海马齿状回门区和ＣＡ１区内可见散在的凋亡神经元,凋亡神经元主要表现为核周染色体的聚集和凝结成块,其核膜表现为皱缩和扭曲,在晚期凋亡的神经元有时可见核膜破裂。凋亡神经元胞浆内的细胞器保持完整。　结论　凋亡参与了海人酸诱发癫痫发作后海马内神经元的死亡过程。     

神经肽Y的基因及其表达调控

神经肽酪氨酸(NPY)是一种含36个氨基酸残基的生物活性多肽,在体内具有收缩血管,影响激素分泌,调节生物节律及摄食行为等多种生物学功能。本文从NPY cDNA克隆、基因结构与功能关系以及多种因素对其基因表达的调节等方面作一综述。     

Differential changes in messenger RNA expressions and binding sites of neuropeptide Y Y1, Y2 and Y5 receptors in the hippocampus of an epileptic mutant rat: Noda epileptic rat

The anti-convulsive effects of neuropeptide Y have been suggested in several animal models of epilepsy. We have found the sustained increase of neuropeptide Y contents and the seizure-induced elevation of hippocampal messenger RNA in a novel spontaneous epileptic mutant rat: Noda epileptic rat. In the present study, we investigated the change of neuropeptide Y Y1 and Y2 receptor messenger RNA expressions and binding sites in the hippocampus following a spontaneous generalized tonic-clonic seizure of Noda epileptic rat. Furthermore, the binding sites of a more recently isolated receptor subtype, neuropeptide Y Y5 receptors, were also evaluated by receptor autoradiography. A marked elevation of neuropeptide Y immunoreactivity in the mossy fiber, and Y2-receptor up-regulation in the dentate gyrus were observed in the hippocampus of Noda epileptic rat, which coincided with the previous results of the other epileptic models. In contrast, Y1-receptor down-regulation was not found after a spontaneous seizure of Noda epileptic rat while this occurs in kindling and after kainic acid-induced seizures. [125I][Leu31, Pro34]peptide YY/BIBP 3226-insensitive (Y5 receptor) binding sites in CA1 stratum radiatum were significantly decreased following a spontaneous seizure of Noda epileptic rat. The present results suggest that a spontaneous seizure of Noda epileptic rat induces significant changes in neuropeptide Y-mediated transmission in the hippocampus via Y2 and Y5 receptors, but not Y1 receptors. Therefore, specific subset of neuropeptide Y receptor subtypes might be involved in the epileptogenesis of Noda epileptic rat.     

N-methyl-D-aspartate receptor complex modulation by neuropeptide Y and peptide YY in rat hippocampus in vitro

Neuropeptide Y (NPY) and peptide YY (PYY) are known to bind with high affinity to sigma (sigma) and phencyclidine (PCP) binding sites in rat brain. The functional significance of these results was assessed by testing both peptides in an in vitro bioassay system used for studying the N-methyl-D-aspartate (NMDA) receptor and consisting of rat hippocampal slices preloaded with [3H]noradrenaline (NA) and maintained under superfusion. The addition of NMDA in the superfusion medium induced an efflux of [3H]NA from the slices and the presence of NPY and PYY produced an enhancement of the stimulating effect. These results suggest that NPY and PYY could have a modulatory role at the NMDA receptor complex through an interaction with the sigma and/or PCP receptor.     

低氧预适应后小鼠海马神经肽Y及突触的变化

目的 探讨低氧预适应产生神经保护作用的机制。方法 将小鼠随机分为对照组（H0组）和低氧组（H4组）,H4组为通过整体重复低氧建立的小鼠低氧预适应动物模型,H0组不进行低氧处理。用免疫组织化学方法检测小鼠海马神经肽Y(NPY)及突触体素（SYP）的表达,电镜观察海马CA1区的不对称突触和穿通型不对称突触形态及数量。结果 与H0组相比较,H4组海马NPY阳性细胞数量有中等量增多(n=30),SYP阳性细胞数量有明显增多(n=30),而海马CA1区的不对称突触和穿通型不对称突触数量减少(n=6)。结论 低氧预适应后海马的这些变化可能降低了神经元的兴奋性,从而增强了脑抵抗低氧/缺血的能力而产生神经保护作用。     

Changes in interneuronal phenotypes regulated by estradiol in the adult rat hippocampus: a potential role for neuropeptide Y

Ovarian hormones regulate pyramidal cell synapse formation and excitability and interneuronal GABAergic tone in the CA1 region of the adult female rat hippocampus. The role of 17beta-estradiol in these effects is complex and appears to involve a subset of hippocampal interneurons, which express different calcium-binding protein and neuropeptide phenotypes and nuclear estrogen receptor alpha. We found that, in the hippocampus, nuclear estrogen receptor alpha-immunoreactive interneurons co-express neuropeptide Y, calbindin-D28k and calretinin but do not parvalbumin or cholecystokinin. Moreover, a proportion of neuropeptide Y-immunoreactive interneurons co-expresses calbindin-D28k and calretinin. This pattern is similar in the presence or absence of 17beta-estradiol treatment in ovariectomized rats. We then used immunohistochemistry and in situ hybridization to determine whether 17beta-estradiol treatment regulates expression of CA1 interneuronal phenotypic markers via nuclear estrogen receptor alpha activation. We found that 17beta-estradiol treatment of ovariectomized rats increased neuropeptide Y mRNA levels (25%) and the neuropeptide Y mRNA-associated grain density per cell (11%), as well as the number of neuropeptide Y-immunoreactive cells (11%), predominantly in the pyramidal cell layer (stratum pyramidale). Treatment with CI628, a selective estrogen response modulator that acts as an antagonist for nuclear estrogen receptor, blocked 17beta-estradiol-induced increase of neuropeptide Y mRNA levels. 17beta-Estradiol treatment did not alter the number of parvalbumin, calretinin, and cholecystokinin immunoreactive cells, nor mRNA levels for parvalbumin and cholecystokinin. Therefore, the present study has identified neuropeptide Y expression as the main interneuronal phenotype that co-expresses nuclear estrogen receptor alpha and shown that neuropeptide Y is responsive to 17beta-estradiol in CA1 pyramidal cell layer. We suggest that 17beta-estradiol may regulate neuropeptide Y expression mediated by nuclear estrogen receptor alpha-dependent activation in a subset of hippocampal interneurons, and we speculate that subsequent neuropeptide Y release may indirectly contribute to regulate glutamate-dependent neuronal activity in the adult rat hippocampus.     

Distribution of neuropeptide Y receptors in the rat hippocampal region

The distribution of binding sites for neuropeptide Y (NPY) was studied in the rat hippocampal region by using [3H]NPY together with quantitative in vitro receptor autoradiography. The highest density of specifically bound [3H]NPY was found in regio superior and regio inferior of Ammon's horn. Within these fields, stratum oriens, stratum pyramidale and stratum radiatum harboured the highest densities of [3H]NPY binding while stratum moleculare was relatively poor in [3H]NPY binding sites. In area dentata, the highest density of [3H]NPY binding was found in the inner one third of the molecular layer. In the presubiculum and in the entorhinal area, the outer two layers were slightly more enriched in [3H]NPY binding sites than were the deep layers. In all hippocampal subfields a clear gradient of increased [3H]NPY binding was found at successively more ventral levels.     

Inhibitory effect of 5-hydroxytryptamine on hyperphagia in mice with genetic overexpression of neuropeptide Y

The present study examined the effect of 5-hydroxytraptamine (5-HT) on the feeding behavior of transgenic mice with neuropeptide Y (NPY) overexpression. Solution of 5-HT (1, 2.5 or 5 mg/kg) was administered intraperitoneally into (1) NPY-overexpressing mice, and (2) wild-type mice with 2-deoxy-d-glucose (2-DG) induced hyperphagia. The NPY-overexpressing mice were further divided into five groups: (1) control mice, (2) mice treated with 5-HT (5 mg/kg), (3) mice treated with 5-HT (5 mg/kg) and ketanserin (0.5 or 1 mg/kg), a 5-HT2A receptor antagonist, (4) mice treated with insulin (1 IU/kg), and (5) mice treated with insulin (1 IU/kg) and 5-HT (5 mg/kg). Food intake and plasma glucose levels were measured. The results showed that 5-HT reduced hyperphagia in both NPY-overexpressing mice and 2-DG-treated mice in dose-dependent manner. Hyperglycemia was induced by 5-HT administration. Ketanserin antagonized the 5-HT induced hypophagia and hyperglycemia. Insulin, on the other hand, prevented 5-HT induced hyperglycemia but not the hypophagic effect. In conclusion, 5-HT reduces hyperphagia in the NPY-overexpressing rat through action on 5-HT2A receptors and this hypophagic effect of 5-HT does not depend on the hyperglycemia.     

Somatostatin and neuropeptide Y in organotypic slice cultures of the rat hippocampus: an immunocytochemical and in situ hybridization study.

The neuronal distributions of somatostatin and neuropeptide Y and their respective mRNAs in hippocampal slice cultures were examined by immunohistochemical staining and in situ hybridization. For the in situ hybridization we used an alkaline phosphatase-labelled oligodeoxynucleotide probe for somatostatin mRNA and an 35S-labelled oligodeoxynucleotide probe for neuropeptide Y mRNA. For both neuropeptides the immunostained and hybridized neurons displayed a comparable, organotypic distribution. Most labelled neurons were located in the dentate hilus and stratum oriens of CA3 and CA1. Additional neurons were found in stratum radiatum and pyramidale of CA3, but very few in the corresponding layers of CA1. In all locations the density of somatostatin- and neuropeptide Y-reactive cells exceeded that observed in vivo. Also, the hybridization signal of the individual neurons appeared enhanced in the slice cultures. Methodologically it was noted that the non-radioactive alkaline phosphatase-labelled oligodeoxynucleotide probe gave excellent in situ hybridization results with detailed cellular resolution and no apparent problems of tissue penetration, even when used on whole-mount explants. These results demonstrate that somatostatin and neuropeptide Y-immunoreactive and mRNA containing neurons retain their organotypic distribution and basic morphological characteristics in the slice cultures. The supernormal density of these neurons and their hybridization signals indicate that a transient developmental increase in neuropeptide expression may persist in vitro.     

Pancreatic polypeptide immunoreactivity in rat brain is actually neuropeptide Y

Radioimmunoassay was combined with high pressure liquid chromatography and immunohistochemistry to establish the identity of pancreatic polypeptide-like immunoreactive material in the central nervous system of the rat. Antisera to avian pancreatic polypeptide, bovine pancreatic polypeptide, the invariant amidated carboxyterminal hexapeptide fragment of mammalian pancreatic polypeptides and the structurally related peptide, neuropeptide Y, were used immunocytochemically to localize neurons containing immunoreactive pancreatic polypeptide-like material in rat brain. Adjacent brain sections stained by the indirect immunofluorescent technique and single sections from double-staining experiments demonstrated that identical fibers and perikarya stained for pancreatic polypeptide-like immunoreactive material by antisera directed against each of the four peptides. Characterization of pancreatic polypeptide-like immunoreactive material in chromatographed rat brain extracts by radioimmunoassay using antisera to either neuropeptide Y or the carboxy-terminal portion of the pancreatic polypeptide molecule revealed that the major peak of immunoreactive material, as measured by either assay, appeared to co-elute with synthetic porcine neuropeptide Y. A minor peak of immunoreactive material co-eluting with peptide YY standard was indicated by the neuropeptide Y radioimmunoassay. This was contrasted by data obtained from chromatographic profiles of rat pancreas, which showed that the main immunoreactive peak, as measured by the neuropeptide Y assay, co-eluted with porcine peptide YY, with a minor peak co-eluting with porcine neuropeptide Y. The main peak of immunoreactive material in pancreas, as measured by the pancreatic polypeptide carboxy-terminal radioimmunoassay, eluted considerably earlier than standard peptide YY, neuropeptide Y and bovine pancreatic polypeptide, and is probably identical to rat pancreatic polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS)     

Y5 receptors mediate neuropeptide Y actions at excitatory synapses in area CA3 of the mouse hippocampus.

Neuropeptide Y (NPY) is a potent modulator of excitatory synaptic transmission and limbic seizures. NPY is abundantly expressed in the dentate gyrus and is thought to modulate hippocampal excitability via activation of presynaptic Y2 receptors (Y2R). Here we demonstrate that NPY, and commonly used Y2R-preferring (NPY(13-36)) and Y5 receptor (Y5R)-preferring ([D-Trp(32)]NPY and hPP) peptide agonists, evoke similar levels of inhibition at excitatory CA3 synapses in hippocampal slices from wild-type control mice (WT). In contrast, NPYergic inhibition of excitatory CA3 synaptic transmission is absent in mice lacking the Y5R subtype (Y5R KO). In both analyses of evoked population spike activity and spontaneous excitatory postsynaptic synaptic currents (EPSCs), NPY agonists induced powerful inhibitory effects in all hippocampal slices from WT mice, whereas these peptides had no effect in slices from Y5R KO mice. In slices from WT mice, NPY (and NPY receptor-preferring agonists) reduced the frequency of spontaneous EPSCs but had no effect on sEPSC amplitude, rise time, or decay time. Furthermore, NPYergic modulation of spontaneous EPSCs in WT mice was mimicked by bath application of a novel Y5R-selective peptide agonist ([cpp]hPP) but not the selective Y2R agonist ([ahx(5-24)]NPY). In situ hybridization was used to confirm the presence of NPY, Y2, and Y5 mRNA in the hippocampus of WT mice and the absence of Y5R in knockout mice. These results suggest that the Y5 receptor subtype, previously believed to mediate food intake, plays a critical role in modulation of hippocampal excitatory transmission at the hilar-to-CA3 synapse in the mouse.     

Influence of imipramine on neuropeptide Y immunoreactivity in the rat brain

The effects of treatment with the antidepressant drug imipramine on neuropeptide Y immunoreactivity were studied immunocytochemically in the rat brain cortex and hypothalamus. It was found that the level of neuropeptide Y immunoreactivity in the cortex was significantly lowered three and 24 h after the last dose of chronic (14 days) imipramine administration as well as 3 h after acute administration. A tendency to decrease neuropeptide Y immunoreactivity was also found in the hypothalamus. The results obtained suggest an important role of the cortical neuropeptide Y in the action of the drug.